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Custom or general model: compare the work your team actually does
Short answer
You compare a custom model with a general one on the same cases and under the same conditions: how many corrections remain for the employee, how long they wait for an answer and who maintains the extra version. A better first draft does not always justify the cost of maintenance.
How we workDetails ↓
- 01Call30 minutes with an engineer, free
- 02PrototypeA working system on your process and data, free
- 03ImplementationTarget and fixed price in the contract; 50% at signing
- 04Acceptance50% once the agreed target is met
- model on your server or in the cloud in the EU
- quoted after the review
- same work in application with EU cloud model
- from €3,000
- task, data and equipment analysis
- €0
We belong to the OpenAI and Anthropic partner programmes and learn through their official courses. What this means ↓
Author: Syntalith · 3 min read
Statistics
Custom and general models: statistics 2026
33 h
a month fewer corrections at 1,000 drafts: a general model with an instruction cuts errors from 30% to 18%, fine-tuning to 10%. Scenario.
14–56%
According to Anthropic (2025), AI cut task time by 14 to 56% in studies with a control group.
Source: Anthropic, Estimating AI productivity gains (2025) ↗
25.1%
According to a Harvard Business School study (2023) of 758 consultants, tasks within the model's capabilities went 25.1% faster with AI.
50%
According to the European Commission (2026), half of the small and medium-sized companies in the EU name high investment costs as a barrier to AI.
Source: European Commission, Flash Eurobarometer 578 (2026) ↗
20.0%
According to Eurostat (2025), 20.0% of EU companies with at least 10 employees used AI.
Source: Eurostat, 20% of EU enterprises use AI technologies (2025) ↗
Figures checked: 22 October 2026
The comparison covers all the work around an answer. The employee waits for the draft, checks it and corrects it, and the company maintains an extra version of the tool, repeats the assessment after changes and looks after the set of examples. According to a Harvard Business School study (2023), tasks within the model's capabilities went 25.1% faster with AI, so a general model is often enough for tasks it understands well.
- The same cases, which neither model has seen
- The same prompt and input data
- The same way of assessing corrections
- Waiting time under a realistic load
Comparable conditions matter
Suppose a team writes short product descriptions from approved product sheets. The adapted model produces text closer to the expected layout. The ready model, though, gets only a general prompt, without the same sheets and guidance. Such a demo does not explain what the extra training gave, because the two solutions worked under different conditions.
In a fair comparison, the team agrees the task, supplies the right information and checks a sensibly prepared base version. It may turn out that changing the instruction or the template removes much of the difference. Only the errors that remain show what adaptation would improve.
Hugging Face points out that evaluating a model on the material used to train it can give misleading results. So the company needs separate cases for the comparison. Everyday tasks show how much work remains for the team.
What the decision-maker receives
Keep the employee's notes next to the answers: what they had to add, delete or check at the source. A verdict of „better” does not explain whether the model saved editing or only pleased the reviewer. Also look at the situations where neither model had enough data.
In the example, a product description may be concise and well written, yet contain a feature that is not on the sheet. That is a different correction from changing the order of sentences. The team decides which errors make the text hard to use, and the contractor shows them separately when discussing the results.
The decision also includes the waiting time for an answer and the handling of changes. An adapted version needs an owner who will assess new errors and agree the next update. Ask whether the advantage stays significant once this work is counted. Without the company's data, do not translate it into promised savings.
The result may justify a narrower scope
A custom model may help with harder descriptions, while a template handles simple products well. The company does not have to cover all the work with an extra solution only because it worked in one part. You can keep the current way of working where it is good enough.
When ordering a comparison, the client names the task and the people who can judge how useful the answers are. Syntalith chooses the variants to compare and presents the result with its limits. The scope of any further rollout follows from that conversation, with no default promise of training.
Describe the correction you would like to reduce and the tool you use today. That is the start of a conversation about comparing models. We price a private model after a free conversation about the task, the data and the hardware. An application that uses the model starts from €3,000 net (pricing).
What it costs
- Today: 30% errors × 1,000 × 10 min
- 50 h (€1,745)
- After a change without training (a general model with an instruction): 18%
- 30 h (€1,047)
- After fine-tuning: 10%
- 16.7 h (€582)
Fine-tuning adds 13.3 h (€465) a month beyond the simpler change
The error shares and the correction time are the scenario's assumptions, which we measure on cases not used for training. €34.90 an hour is the EU average hourly labour cost for 2025 according to Eurostat.
- Cases for assessment kept apart from training examples
- The same set for the current solution, the simpler change and the new model
- Decisions by the people who correct the results today
- Errors counted separately for each kind of mistake
Where to start
In the free review we choose one process and 20 to 100 cases the team has already handled. We compare the simpler change with an adapted model on cases the model has not seen, and within 2 working days you receive a written summary with a price. We adapt models as part of private LLMs, and build the application as part of AI apps.
Worked example · Scenario
How we count the payback: a custom model
We run the same count for your team in the free review.
€4,188
a month for the work on 600 questions
EU cloud version payback: 0.8 mo.
Our assumptions are 12 minutes to find an answer in the documentation, and checking in 15% of the old time. €34.90 an hour is the EU average hourly labour cost for 2025 according to Eurostat, for companies with 10 or more employees. Model cost: Claude Sonnet 5.5, about 6,000 + 500 tokens per answer in the EU cloud version, at the ECB rate of 1.1205 USD per euro on 22 October 2026. We count the payback for an app with a model in the EU cloud (from €3,000 net). We price the model on your server after a call, and the cost of people's work stays the same.
See the full calculation →