Hello Confusedbyhype;
In the first place you will never get a GIA or AGS cert to be exactly the same as a Sarin report. You will probably never get two Sarin reports from two differenct machines to be exactly the same and you are lucky to get two reports from the same machine to be the same. BUT...they are all close.
The problem is a .5% difference can change the AGA cut grade
either up or down which upsets engineering types. Boy & girls, diamond grading is not an exact science!!! Take your eyes off the numbers and LOOK AT YOUR DIAMOND! Just because a number is .05mm or .5% different is not going to change how it looks. The Sarin, Leveredge Guage or micrometer could be off by .05mm.
Oh, the AGA cut chart is not a GIA thing, but it will do until GIA gets off their dead thing and comes up with one of its own. Who knows, maybe GIA will take a short cut and buy the AGA cut chart from Mr. Atlas. NOT!