Interesting Question
privador,
If you get back 6 units on an 11 unit bet by surrendering, that means that the EV for surrender is -5/11 = -0.454545, instead of -0.500000 for "normal" surrender. Since surrendering is less costly for you, you should do it more often.
To get the answers for BS is easy, as shown below:
You didn't specify the house rules, so I'll pick 6D, S17, DA2, DAS. Now with the help of Tables A50-A59 from Don Schlesinger's Blackjack Attack 3, all we need to do is find which BS plays have EV's less than -0.454545. In addition to all the usual surrenders (16 (but not 8-8) vs. 9, X, and A, and 15 vs. X) you'll also surrender 14 (including 7-7) vs. X, 8-8 vs. X, 15 vs. 9, and both 15 and 17 vs. A. The closest call is 16 vs. 8, for which hitting has an EV of -0.453130 (for X,6) or -0.453627 (for 9,7), but since both values are larger than -0.454545, you should Hit 16 vs. 8.
If you're facing other rules, simply check the appropriate tables and perform the same type of calculation.
On the other hand, if you need to get new surrender indexes, you'll have to run a simulation to get the EV's at various counts.
I have a question for you: if you surrender a bet of 110, do you get 60, or just 55?
Hope this helps!
Dog Hand