It's quite normal to loose pay when you are earning most of your income on a 'productivity' basis. It doesn't really matter as you will make it up in the other months. As long as you fly close to the maximum hrs per year it is what it is. I'm up at 850hrs already for the last 12 months. And that's almost double what I was used to at other airlines.
PBS is not working like we pilots want it too because we are soooo short of crew. PBS is there to assign work and the company policy seems to be to understaff us and get the maximum out of each and everyone. PBS is not a given right to a better roster but a tool to make life better IF the numbers add up. And they don't. If there is 'excess fat' commercial will just add flights and they will have to be staffed. So the senior guys take a hit too and everyone complains. It will only get better if the number of pilots in both seats go up big time. And I don't see that happening anytime soon...