Your code fragment has undefined behavior because you are writing to Sched_0_Fctn_Ctr twice between sequence points. That is, it is not legal C code. You need to write it like this:
if (Sched_0_Fctn_Ctr >= CYCLE_SCHED_0 ) Sched_0_Fctn_Ctr = 0; else Sched_0_Fctn_Ctr++;
or like this if you intended the increment to come first:
Sched_0_Fctn_Ctr++; if (Sched_0_Fctn_Ctr >= CYCLE_SCHED_0 ) Sched_0_Fctn_Ctr = 0;
[ Edited after posting -- Archaeologist ]