I'm not sure on Heidenhain, we have Millplus,
What values are you puttinig into the rad. comp ?
If you are using R=0.0 in the machine, then your mate is either using "wear" or "computer"
If you are using R=(1/2 tool diameter) in the machine, then he's using "control"
Tool compensation can only be done on paths using "control", "wear" or "reverse wear"
"wear" says it all, it allows for small +-adjustments, regrinds, etc. not large over-compensations, like a 1" tool path over-comped for a 2" cutter.
Sometimes, the machine's parameters cause tangency errors on a compensating toolpath.
"control" on the other hand allows for this situation, the actual toolpath is the comp to profile, as long as the lead in and out accommodate the tool and there is no internal arcs smaller than the tool radius, then all should be OK
The only danger is the these methods cannot be mixed on the same tool( the control may allow R1=0 and R2=tool rad )( ie T1R1L1 is a different tool to T1R2L1) but like I said not sure on Heidenhain