It could be SS, with this base anyway, my usual base doesn't need as much reduction.
But dont forget a Balti has a lot more flavour than a standard chicken curry, hence its thicker.
Im with jerrym also about the fact that im surprised about how much spices dip used, i never use this much usually. Thing is it works here.
Its a bit weird really. You'd think it would be over spiced.
Im thinking that once the spices are fried they reach maximum flavour, and then with further cooking/simmereing/boiling they actually mellow out. Its something i have noticed before with bases, the longer you cook them the more subtle the spiceiness.
The trade off being you have to boil away the rawness of your bonions, and at the same time make sure your spices reach the right level of flavouring at the right time.