Currently FME Server is routing jobs to available engines with the round robin circulation. One of the main benefits of dynamic engines is that job can use these (only) if there is peak demand. Currently jobs can also be assigned to dynamic engines if a standard engine is available but the circulation system decides to use the dynamic engine.
My suggestion is to have FME Server 'see' dynamic engines differently than standard engines to be able to only assign jobs to dynamic engines if no standard engine is available.
With this we don't have to pay for standard engines that are idle most of the time, can use dynamic engines only when needed and we don't lose credits on using dynamic engines when a standard engine is available.
See also discussion here.
