Calculating Man Hours in P6

I resource loaded my activities using a 5D/10HR calendar to calculate my manhours by each craft/discipline. I have gone to User Preferences/Calculations and I have the button set to Recalculate the Units/Duration etc. button. I went to Enterprise and resources and have it defaulted to 10H/D. When I change my resources it does NOT recalc my manhours. And if I rollup my discipline/craft to summarize my duration and budgeted units the totals are not accurate if you add them up manually. I have my activity type set as Fixed Duration/Units.

What am I missing?

Thanks in advance. Beth