hi Juliet.
just want to be sure you are clear about the dosage stability. as Mel is saying you need to pick a dose that you can shoot twice a day without changing it each time you shoot. so right now, it is much better to have him be a little high and give a consistent dose. you don't want to change the dose every time you shoot. if he is dropping so low that you have to skip a shot or reduce the dose then the dose is too high right now. if 1 unit is your chosen dose then you need to shoot 1 unit morning and night for maybe a week to let his shed fill properly and let the dose settle. then maybe next weekend you can run your full curve. you can spot check until then but don't worry about his numbers riding a little high for this week. you need to first flatten his curve a bit so he doesn't get these steep and fast drops. and as Áine is saying...forcing him into blues that he is not ready for will.just cause major bouncing and is not really the best thing for him.
i would do exactly as Mel has advised and do 1 unit twice a day for a few days, then post his numbers and we can go from there. but start with lower dose (1 unit both day and night) and don't change it for a few days.
if he still drops too low on 1 unit, then you may have to go back and start at .5 twice a day for a week. the goal at first is consistent dose am & pm and a nice flatter curve. after you achieve this, then you can start increasing slowly to eventually get his numbers down