Early Surrender – This less and less available rule allows surrender of a
hand before the dealer checks for Blackjack. If you can find a casino
that allows it, this is one of the most valuable options in the game. Advantage
is about .6-.7. It can be found in Africa, some places in Eastern Europe, for a
time in Moscow, a couple of casinos in Vancouver and a handful of casinos in
Western Europe. In rare cases, you will find a dealer that allows this because
she does not understand the late surrender rule. ("Modern Blackjack" P.30)

I found (only) a casino offering Early Surrender on any dealer up card (Not against Ace).
When dealer has Ace up, he check hole card. If it is not BJ, then still surrender is available. (Do we call this 'Late Surrender ?)

Common rule in this city is; 6D H17 DAS RSA ENHC (OBO) SPL3 ES (NS against Ace).
Because dealer don't draw hole card, players can't surender.
MGP's BJCA show net EV of these rules as -0.307%.

I didn't realize the value of "Early Surrender" which offered by that (only) casino.
It is NOT ES10, surrender any up cards., even against Ace after peek.
MGP's BJCA show net EV as +0.165 %. (I can't believe this !!!)

How can I reap this golden opportunity ? So far, I avoided this casino, beause penetration is not great (not bad, 4.5/6).
Difference with other casinos is options to surrender more (against Ace). Is it really so valuable to turn negative EV to positive ?

Copy from other thread; Biggest benefit is massive reduction in flux plus the offset of the house edge enabling you to bet significantly bigger at each true count...basically you move up your entire bet ramp by one notch and that has a huge impact on your win-rate. (BigPlayer)

Please give me any advice to vary playing.