If you have the following flight time,
250 hours of flight time, 100 hours of which must be in powered aircraft, and 50 must be in airplanes. 100 hours of pilot-in-command time, 50 of which must be in airplanes. 50 hours of cross-country time, 10 of which must be in an airplane.
If you have all of these then you just have to show proficiency in the FAA maneuvers for the CPL test and the head instructor must be satisfied you are ready for the test. Any school telling you that all the training flights must be undertaken like you are a zero hour student is telling you b*llsh*t.
To take the IR these are the requirements,
Fifty (50) hours of cross-country flight time as pilot in command, of which 10 hours must be in an airplane AND:Forty (40) hours of actual or simulated instrument time, of which 15 hours must be received from an authorized instructor who holds an instrument-airplane rating.
If you can show an instructor you know what to do and have the flight time, you can do the checkride. Both the written CPL and IR test must be completed too of course.
The only EASA hours that don't count in FAA land are PICUS/ICUS or whatever it's called now.