hi there
@yule1yule
that does make things a bit more difficult.
as Humulin I is an intermediate isophane insulin , it lasts around 16 -24 hours and although not critical that it is taken at the exact same time each day - it is just an extra amount of variability in your daily routine you could do without.
are you testing your blood sugars at all ??
monitoring your blood sugars on a daily basis at the same times ( upon waking ) or just before you eat , will give you a picture of whether the timing of doses is having an impact on your blood glucose levels.