"Also, there was a bug in the trading routine. Instead of getting a bonus for bringing cargo from a higher tech system to a lower one, the opposite was true. I sent GDW a ltr explaining the problem"

Nahhh, you saw the wrong problem.

The actual problem is that, under the Merchant Prince rules as written, lo-tech worlds run a massive Imperial Credit deficit they cannot solve, because under the rules as written, they all want to import lo-tech goods and hi-tech worlds dont want their exports.

If you have floating local currencies, then you can just devalue your local currency, so whatever it is you produce is cheaper and whatever you import is more expensive, and both TCS and Striker kind of did this ... this would therefore eliminate the DRM, as lotech hand-made shoes or shirts or paintings or whatever are sold for export for nearly nothing.

But this implies that lower-tech goods should be much, much cheaper in Trav than they are.

TLDR : If you want a realistic universe, then either you have a lot of people working elsewhere and sending money home (which could explain all those "low pop" worlds - they have very few citizens and lots of imported guest workers), or you had lots of hi-tech workers visiting lo-tech worlds (but two jumps is roughly a years income for a TL15 citizen on average Striker earnings).