Yes we quite often do that, bolus for main course + correction and then a little while later bolus for pudding, because daughter hasn’t always decided what she wants for pudding! Just don’t do a correction dose the second time even if you’re higher, because the insulin from the first dose will still be working. (Your bolus adviser should know this and if you did the correction the first time then it won’t allow another one a short time later.)
We have always used pumps and just input the carbs into the bolus adviser on those, and it decides how much - pumps can do ridiculously tiny corrections so I don’t see the problem with only doing one unit for correction as long as you don’t do another one within a short time. However, I find if you can possibly do one bolus for everything rather than several small ones it seems to work better, not sure why, I think this is the issue with stacking that if you have several doses going round from different times the effects can sometimes be a bit unpredictable.