I'm using conditional statement in my php header to exclude some of files from being followed by robots. However temporarily I have to block some of these pages because my website is under performing. At this stage I've used robots.txt to exclude them. But they still have meta index no follow.
Would that contradiction be seen bad by Google?
If you are blocking the pages in robots.txt, then any crawler that obeys robots.txt will never load the page, and will therefore never see the robots meta tags. The meta tags are effectively ignored.