from the data sheet

"The ISR determines the source of the interrupt by
polling the interrupt flag bits. The interrupt flag bits must
be cleared before exiting the ISR to avoid repeated
interrupts. Because the GIE bit is cleared, any interrupt
that occurs while executing the ISR will be recorded
through its interrupt flag, but will not cause the
processor to redirect to the interrupt vector."

therefore since your overflow routine is an isr the int_disable lines are redundant and just waste time .
since position is not important to lose a pulse woud probably not matter