Why didn't the bitcoin-qt show that immediately after the rescan?
All I can think of is that somehow your Bitcoin Core wasn't synced completely. I've done this same procedure before, and it always worked out just fine.
I do have two recommendations for the future:
1. Use smaller amounts to get familiar with paper wallets. Instead of testing things with $800, use $2.
2.
Before funding a paper wallet, import the address (
not the private key!) into Bitcoin Core:
importaddress 1addy PaperWallet1addy false
The "false" prevents a rescan. If you fund the paper wallet after this, it shows up as Watch-only and the balance is nicely updated. Since Bitcoin Core now knows your balance, you can later import the private key without a rescan.