Since you clarified, I guess you're not as far off the path as I thought, but I still think you should only move up when you hit 30 buyins and move down as soon as you hit 20 buyins for the level you're at. To me, that's not nitty or too conservative and I wouldn't bend the rules because it's micros. If you bend the rules, ALWAYS bend them to be more conservative. It seems like the majority of threads I read where people have to move down, they either didn't follow bankroll management at all OR the rules they followed were too liberal like 15 to 20 buyins for NL. Much less frequent is the player who follows a 30 buyin or more strategy who finds himself having to move down one or more levels. Losing your money or bankroll or moving up too soon is a MUCH bigger problem than possibly having more money than you need for the next level or moving up too late. EVERYONE has a glass ceiling on how far up they can move before there are either no more games or a level they can't beat. Poker is EVERYWHERE 365/24/7, so don't be in too much of a rush

The reason 30 buyins is such a solid # in my opinion is because of how it relates to 5%. If you ever do any statistical analysis or have a thesis to prove, the magic # is usually 5%. You might state a null hypothesis like "There is NO relationship between x and y" and then you do a study or run some tests across a high sample. If you get a positive correlation 95% or more or NOT a correlation 5% or less of the time, then SOMETHING is going on and there is indeed a relationship and you have to reject the null hypothesis. As it relates to poker, 95% is the percent of the time that solid poker will win you money and 5% is the percent of time that variance or the occasional bad play will cost you money in the long run. 5% is 1 out of 20, thus 20 buyins. BUT, we bump that up to 30 to give us some cushion and wiggle room @ about 3.33% OR 50% more buyins compared to 20. Then, when we drop to 20 buyins, we are basically admitting that there is a good chance SOMETHING is going on with our play at the level we're at - bad play, variance, or whatever. Drop down a level, work it out, move back up a level when bankroll results dictate, and try again.

Obviously we all need to do what we feel is best for us and there isn't necessarily a right or wrong answer, but I just think it's better to have a solid plan in place and only error to the side of caution.