I don't have exact numbers as I was not involved with the distribution, but as far as I know, over 95% of the investors claimed their BCC/BCH (we're talking about a group of ~500 people).
That's ~$20,000 USD of investor money left on the table. It seems like CG is being compensated quite well with this fork.
That number is based on usercount, not investment amount, eg an investor with 100
BTC claimed would influence it the same way as one with 0.01
BTC unclaimed.
For reference, the current bankroll is 1649
BTC, of which 1103
BTC // 67% are provided by a group of only 10 people (1358
BTC by a group of 20 people // 82%).
I'd expect the actual number of BCH left unclaimed way below your calculated 65.
The terms on which the users invested in the site bankroll doesn't have any reference about giving a forked coin. Yet, crypto-games handled the unexpected situation favoring its users. Handling of BCH (claiming, storing and dividing between users) surely was a extra bit of work for the site and There's no place to blame the site for not being able to claim the BCH within the stated deadline.