Bar numbers

I would like to see the bar numbers be able to go under the measures. I would also like to see letters be able to be used after the measure number as you see in musical theater scoring. Such as 142 142A 142B 142C 142D and so on. When charts are produced by Concord Theatricals for example, they will do that at times in response to the evolution of a score. If I have to rechart something in Noteflight, I am unable to have the measure number and letter match the rest of the score.