[Avodah] Ul'chporas Pawha

[cantorwolberg at cox.net]

I wonder why we say it only on Rosh Chodesh Cheshvan to Nissan, and not every Rosh Chodesh for the entire year. 

Most congregations recite it through the Second Adar because it is obviously added AS A RESULT of the Second Adar. Hence, the feeling was that was the leap year month is over, there is no need to continue saying it. However, there are congregations that recite it for the whole year.
ri