Welcome I am not an expert on the numbers.and it is only in the last 4 months I found out the difference between my test kit readings and a1C which is supposed to equate to a 3 month average.
The a1C in Australian labs is going to change scale but on the old scale the low end readings were similar to my home meter but as the numbers rise they get further apart. a1C of around 6.4 actually equated to 8 + on my home meter and the higher they go the further apart they become.I am not sure what your 7.2 equates to but my guess is up around 10 .
6.3 a1C will be about 48 on the new scale. 48 is too low for insulin users (risk of going too low) but for non insulin users it could be lower. (according to my specialist)
I am sure it will be on the net somewhere, but I do not need to know so I have not bothered to look it up.