Holytransaction hiding my ZEC?

I have been mining ZEC for several months using flypool. The holytransaction site says i have 1.9 ZEC. I periodically move my ZEC to Trezor which says I have 2.24 ZEC. Add the two together and you get about 4.1 ZEC. After doing the math, it seemed a couple ZEC low.

So, I went to Holytransaction and looked at the transaction log of 0.01 ZEC coming in every few hours, then I eventually switched to 0.1 ZEC increments to cut down on the churn - especially when I found out that every time they send me ZEC, I will have to report the FMV for that day and pay capital gains taxes (US).

When I put the transactions in a spreadsheet (copy and paste since there is no export function), it shows that I should have 4.0 ZEC, not 1.9 ZEC! I double and triple checked the way the spreadsheet was adding things up, and made a running balance column to see if i could figure out if it was a certain point where it went off. What I found is that it drifts off over time, and it’s been wrong since the beginning.

I contacted Holytransaction support and their answer was strange - “Your deposit address is binded to your account forever. All deposits made to this address will be added to your account balance. However we don’t guarantee that coins will reside on this address. Due to our system architecture and security measures coins will be moved to other addresses shortly after deposits, but it does not affect your account balance. You can still spend all your money at any time.”

I replied asking for more detailed information yesterday but haven’t gotten an answer yet. My only theory is that they have the ZEC already but it hasn’t hit my account. I’m going to move my mining rewards to another wallet and let that account sit to see if it eventually shows the correct amount.

Has anyone seen behavior like this? I’m mining using a 9 GPU rig with EthOS doing about 3000 hash/sec.