Hi Chaitanya - SUP patches are different from Cumulative Patches. Cumulative patches are more like CPS.In your steps, I am wondering why you did not apply the patch after the update, after step#6? What you will have now is SUP11, not PS8. I think you have to install cumulative patch to fix some of the issues. I think it is a good idea to review/compare the readme files of the patch you installed and PS8
Your understanding is correct. The fixes in SUP11 are all included either in the M050 service pack or the M050 cumulative patches. As long as you apply the latest cumulative patch after updating to M050, you will have all the fixes from the M030/M040 SUP11 patch.