I don't see that logic at all Phil. I understand what you are getting at but, he actually says that the gravy, once cooled and re-heated suffers a marked change and deterioration, and yet that is what he suggests in the first place. I believe it is usual in the BIR method to use gravy that is already hot when added to the dish pan and so if it's been cooled, it must be re-heated to use. No matter which way I look at it, I see a contradiction.
Regardless, I have to say that when I cooked this gravy last night, I used it immediately to make the basic chicken curry. I'd pre-cooked the chicken (breast and thigh) by poaching in a weak chicken stock with a bit of mild curry powder. (Knorr Chicken Powder and Clive of India Curry Powder.) The resulting curry was superb. However, I have to agree with other earlier comments in that for some reason the heat from chilli powder appears to be amplified when using this base gravy. As my family is not fond of hot curry, I used only a small amount (about a tsp in a double serve) of "Mild" Chilli Powder and the dish was on the edge for my wife, whereas I and my daughter found it ok. The original recipe calls for a TBSP of Chilli Powder in a single serve for a "serious vindaloo". I won't be going there.
I also made a very basic Masala Prawns using a splash of the gravy and it was also delicious. I regret not trying this gravy earlier and Mrs Livo has already requested that I make a Lamb Curry using the remaining (refrigerated) gravy. She wants to take it to work next week to share for her staff luncheon.
If you've never tried this gravy, or perhaps it's been a while, I recommend giving it a try. Oh, nearly forgot. I only made a 1/2 quantity which is plenty for home use and will easily produce 4 or 5 double serve dishes.