Controlling time intervals in Assembly

[Lucifer666]

I have assembly code laid out in the following structure (I'll use pseudo commands for readability). Its function is to remain in a state for 0.5s then another state for 0.5s, repeatedly.

main:           //do things
                //do things
                //do things

                call ofs //ofs is a 0.5s time delay command
                //do things
                //do things
                //do things

                call ofs //ofs is a 0.5s time delay command
rjmp main

ofs:          //program time delay
              ret

I've re-written it, trying to preserve its functionality, but the result is a 0.5s delay after the first set of 'things' to do and then a 1.5s delay after the second set of things. Why does this happen? Code below:

main:           //do things
                //do things
                //do things

                call ofs //ofs is a 0.5s time delay command
                //do things
                //do things
                //do things


ofs:          //program time delay
              ret
rjmp main