Default Flashing downgrade

So I have seen many say there can be problems when trying to flash a downgrade (older) ROM.... Example...I have CM 10.2; now say I flash CM 11 and don't like it... The story goes that I could encounter problems by attempting to revert back to 10.2..... BUT what if I made a nandroid via CWM recovery of my 10.2 install before I flashed 11? If I didn't like 11, couldn't I just restore my nandroid and be back at 10.2 painlessly?

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