My answer is purely anecdotal, I am a software dev who worked for a distributer that sold Civil Engineering software (it was an application rather than an API/library).

The model was a bit of a gray area, they would sell licenses per user but for larger businesses they would make per business agreements that would mean they could get X licenses for X fee on a per project basis. The nature of Civil Engineering is to work per project, so when a client won a big project for a highway, dam etc. they would hire more Civil Engineers then approach us saying; we are working on project X and need Y licenses what kind of deal can you do. For smaller clients the sales model was simply per user no wiggle room.

My answer is purely anecdotal, but I am a software dev who worked for a distributer that sold civil engineering software. (It was an application rather than an API/library.)

The model was a bit of a gray area: they would sell licenses per user but for larger businesses they would make per-business agreements that would mean they could get X licenses for Y fee on a per-project basis. The nature of civil engineering is to work per project, so when a client won a big project for a highway, dam, etc. they would hire more civil engineers and then approach us saying, "We are working on project X and need Y licenses. What kind of deal can you do?" For smaller clients, the sales model was simply per user with no wiggle room.