Set the Ignition timing and engine runs worse...

Today I decided to check the ignition timing because I never had the time to get in there and set it. I had the CPS adjusting bolt in the center cause it seemed the best place to start and ive been driving it for about 300 miles with it like that and it ran great. Well I got the idle down to 700RPMs, used a wire in the diagnosis box and set it to 10degrees with the timing light and then I put it back together and went for a drive. It now seems like it lost some power like quite a bit. I did everything my TSRM said and now it doesnt run as good.