My hint here is to always write down your mixes, unless they're really simple. I will most often mix a whole batch of paint at once and tape the recipie onto the tub - eg, my take on the 'Orange' Ta 152H colour is 22.0mL of Lifecolor LC55 plus 10.5mL of Lifecolor LC06; And if I am not mixing in a tub, i'll firstly try and keep the mix simple as well make notes of it somewhere - eg, my RLM83 colour is a 1:1 mix of Lifecolour RLM82 (their 'Dark' Green) and FS34079; if I could get some 45-50ml tubs, I'd batch that stuff up too (maybe even 100mL batches. The RLM83 mix took a little while to get right, because I was searching for a 'simple' mixture, so finding the right pair took a few goes...
Dan