3-5mm functional LL discrepency? hah.

that is way within the margin of error for measuring that (which should be taken from navel to malleolus). Heck, you have a bigger quad on one side, that will give you 3mm when measuring.

Even a 3mm true discrepency (taken by measuing an xray).... I havent read any research lately, but there have been arguments for several years at what level does it even play a role (last I heard it was 1-2cm).

Do as you wish. But go find a good PT, let them check you out. You have quite a few structures on/around your 'sit bones'. if you are downtown seattle, I know of a good one. I also know one that is very unimpressive who many cyclists go to.

disclosure - I am a physical therapist and a competitive cyclist.