During a computer practice, I came across the following situation: the count was high enough and I split tens versus 6. On the first hand I hooked an Ace. The game was 6D, DAS, DOA, so I had an option to double down. I wondered if this was the correct play instead of just standing. I made some humble calculations to satisfy my curiosity. According to them, doubling down is a better buy than standing versus 5 and 6, if true count (hi-lo) is 7 or greater. Has somebody been in such a situation on the felt? Of course, splitting tens is not desirable for camouflage reasons. But I think this is mathematically correct (expected value maximizing) play.
Any opinion is welcome.