Bank angle equals load factor increase which is essentially similar to increased weight for performance .. not a really good idea OEI.
Presumably you are aware that the AFM specifies a gradient reduction for climb calculations for turns ?
15 degrees is more than enough to create difficulties with terrain critical departures OEI.
I notice that you have a similar thread in another forum. Against site rules, I'm afraid. I'll leave this one run as it is appropriate to Tech Log. However, please don't run multiple threads as that is a good way to end up in the sin bin.