I simply called and asked how much credit the average Delta pilots gets. You can call crew planning and get the numbers or ask your CP's office. The Caps at Delta average 79 hours a year. You can pick up the cap plus 15. I have been in big and small categories and junior and senior. There is almost always time to pick up to fly to what you want. In 25 years the only situation where I could not fly what I wanted was in a category that was closing. I suspect that applies at the moment to the DC9.
Your total pay in a category is a combination of what you fly, vacation pay, reroute pay, training pay, Greenslip Pay, Assignment Pay ect...
I know lots of pilots who always average over 100. I flew 14 days last DEC and credited 186 hours of pay. I am very comfortable with the 87 hour number per month as a average. Not only is it the number I was given on the phone its the number used as mentioned in flight pay loss calculations last year. Some pilots will be less then that such as a reserve guy in a overmanned category and some will be quite a bit more then that number. Some will be way more then that number.
Lineholder who flies 80 hours average 960
Vacation using 4 weeks 84 hours
training pay 15 hours
one reroute pay event a year 15 hours
2 GS or assignments a years 15 hour trips 60 hours

The above example averages 94 hours a month and is not the least bit unusual. We have a bunch of pilots who will credit way above those amounts. In fact when the 2011 total hours come out the numbers I suspect will be up from 87 average not down. There were a tremendous amount of GS flown both last winter and summer. Normally GS are a mostly summer event. In my category you could essentially fly a GS every month regardless of seniority from last Jan through Aug.
As I mentioned there will be guys who credit way less then 87. A reserve pilot who is in a over manned category is a example. For each guy like that however there is a guy who will credit way more.
Again simply call and ask. Its kind of like the SW pay situation. I post numbers compiled by MIT off the actual airline financial reports and they are called bogus by pilots who produce no numbers themselves. In 2010 the average Delta pilot earned 142,000 in total earnings. 87X12 is 1044 hours. 142,000 divided by 142,000 is 136 dollars an hour. A quick glance at the pay tables suggest that based on fleet size the average copilot pay in 2010 was around 115 a hour and Captains around 162 or so. Devide that out and you get 138 dollars a hour. Those are 12 year rates so the number has to be adjusted down for pilots under 12 years. Probably end up at about 136 a hour which ends up at 87 hours a month. Now show me your math.