Thanks Lordprimate, that did solve the respawning vehicles issue.
Now when the destroyed vehicle respawns, the hint shows that mobile spawn point is again available but doesn't list via the action wheel. The map also shows the mobile spawn points as being deployed and available, so I don't know why they are no longer listed for use. If I don't use your changes and move the vehicle out of the base then destroy it, the vehicle spawns after the time limit and is available on the action wheel again. As a side note, the original vehicle remains where it was destroyed as a burned out hulk.
//SinBad