I have made a few updates to the ElapTimer_Interrupt.pbp include file for this demo.
The new version is 1.1.

Updates:
v1.1 04/06/2015:
1. Added "TcRem" compile-time asm variable.
Used to test for Interrupt Time Accuracy during compile phase.
2. Added compiler test/message for Interrupt Timer Accuracy.
3. Added compiler test/error for TimerConst variable overrun.

ElapTimer_Interrupt.pbp.txt

Don't forget to rename the file by removing the ".txt" at the end of the filename.