Yes, I recall my surprise at the little actual butter used in his Butter Chicken There is only 1 Tbsp of glee/butter in his recipe but 100 mls of cream and the Tomato gravy. From memory though it was quite a nice dish. The method of 3 gravies used in combination and with varying ratios was quite laborious and the quantities took some scaling to achieve home use quantities. My notes from the time on printed sheets remind me that there were problems with amounts that I remember encountering, but in fairness he was providing a commercial process and he tells it as so, that they are huge quantities. My calculations estimate there is enough Gravy in his 3 recipes for about 100 curries.
These gravies are very concentrated in spice levels and flavours. Consequently, only water is added along with them in the dish preparation stages. ie; No normal BIR style Base Gravy at all.
I gave it a try and it worked but it wasn't what I was after at the time. I may revisit the method again now that I have better understanding of curries in general. Unfortunately, he didn't follow up with very many actual dish recipes.