This might be a bit late, but it is a violation of Federal Law to sell reclaimed refrigerant. There is a $25,000 fine per each violation of the EPA rules on refrigerant handling. There is also a 10% finders fee. As for your issue, I would never use R407C in your system. I would use R438a (MO99). It is a 100% drop in with no oil change needed. R438a is so close to R22 that nothing else needs to be done. The conversion is 90% of charge is needed. So a 10# system only needs 9# R438a. A bit late for ya - hope it helps you in the future.