thank you guys for all the comments and replies. I appreciate them and now it is more clear for me :)

As well as grossly over charging the franchise holders, Milo's companies were not actually making anything of greater quality. They were buying stuff at discount retail prices and then selling it on with a huge mark up.

Milo was then transferring the profits from these transactions into overseas accounts with presumably declaring it to the tax authorities.

The bit uncovered by Lewis was the relatively legal side of the operation. It was the money laundering aspect thst crossed a legal line.

" I have to maintain quality"

Love that!

You can tell from the way he says that to both Ruth and Gene that he's convinced HIMSELF. And maybe it's partly true - he could be a con artist AND committed to "quality."

One of the cleverest things about it is how he lectures Columbo about his eating habits and his cigar smoking. The person investigating the murder he committed is the last person he should be lecturing about his health! But being Milo Janus, he can't help it.