Didn't Colm Meany do some film work during DSN's run, which is why he was missing from some episodes.
So it is possible he had a clause in his contract allowing a certain amount of film work
There are over a dozen credits for Meaney released during DS9's run. Some might have been done during the seasonal hiatus (hiatuses? hiati?). He's also on record as saying the producers were very good about arranging his schedule so he could pursue film offers.