I guess XC8 doesn't allow more than

It depends on the clock frequency. There is a maximum number of cycles the delay can be.

 

The builtin __delay_ms() has never worked with 16 bit parameters on the XC8 compile for pic18's... But I'm on the latest V2.05 and it appears to be fixed..

I use pic16's and has always accepted 16 bit parameters..

 

Just for closure... The memcpypgm2ram() was used in C98... It has been abandoned in C99 and simply memcpy() works.. Should have known.. Pitfalls of downloading XC8 v2.05...