If you are a type 1, low carbig can affect both basal and bolus of insulins....this can be much more noticeable if you were on a pump.
I am relating this to a pump, they same sort of principles are for MDI too, and even if you are on a type of insulin which is mixtard...in basic terms...
Your body is set up indivdually by itsel, your DSN and your consultant to run reasonable at set levels really of carbohydrates. FOr pumpers they take in to account what our previous total daily doses were and set us up so that we run at 50% basal to 50% bolus for the carbs that we were eating at the time of set up. If you eat more or eat less, then to keep within that 50/50 ratio we pumpers will more than likely have to alter our bolus and basal ratio's to work good with more or less carbs. A good example of this is for me, when I pig out for birthdays and christmas and any occsion I can make an excuse for, then I do not only alter my bolus upward, both I alter my basals too, in fact even upping them 250% and hour may not be enough when I have pig outs....
Type 2's I believe if they are low carbing can also find that their tablet regime can change.
Also you may be a person that is affected by temperatures and currently needing less during the hotter (April-!!!-LOL!!!) weather....
I think you will find that your ratios of basals and bolus may well alter in line with each. Low carbers for pumps can be set up on a 60/40 ratio rather than 50/50 ratio.
At the end of the day, it doesn't matter how much insulin you have or you are taking. You need to be taking the right insulin for you to keep your levels good.