I think if you count all the planes and helicopters that are either managed or have a service agreement worlwide, 150 could be correct...
From experience, it does not take much time or effort to lose the clients you supposedly "bought" along with the management company, as the present owners of Jet Aviation or Premium Jet could testify...
There had better be some serious brown-nosing of the existing customer base at Execujet going on....
For me the pudding-proof will be how long DD keeps his own 7x at EXJ..