When combining network license files, we found that AEC Collection licenses are consumed before the Building Suite licenses, even when they share the same products. This was not not the expected behavior, as one would think the package with more applications would be pulled last. However, it seems that subscription licenses (ones with an expiration term) are pulled before the permanent ones (non-expiring).
Our scenario involved an office with several seats of AEC Collection for the Revit users, and another few seats of BDS Standard for Autocad users. The Autocad users were consuming from the AECC pool rather than the BDS pool, so some Revit users were unable to obtain a license.
The solution: Introduce an options file with the EXCLUDE statement. We created an options file and within it created a group that included the Autocad-only users. Also made the group non-case sensitive (that was causing an issue). Then exclude the group from the AECC product group as listed in the license file. A quick reread of the license file in LM Tools and the Autocad users were now pulling from the BDS license pool, leaving the AECC pool for the Revit users.
Autodesk article on syntax for the options file can be found here: