I did say "unlike Assembler", wherein you can easily calculate the execution time of each instruction. But even then you are relying on the PICs clock for your accuracy. Let's face it, 20MHz (the speed mentioned by Scottacus - didn't he meet a sticky end at the end of the film?) from a crystal just isn't going to produce 20.000000MHz.

Unfortunately you just can't with PBP. Even execution of a simple a=b+c will depend if the variables reside in Bank0 or elsewhere or if they're Bytes or Words or a mix of both. You can probably have twenty speed permutations of that simple statement alone depending on the conditions I've stated above.