Spectrophotometer Absorbance & Transmittance Measurement

Hi everyone, I’m seeking guidance on converting absorbance values to transmission (%) values and their implications for metrology applications. Here’s my specific case:

If I have an absorbance value A=0.0120A

I’m using the formula:
T(%)=10^−(A)×100
This gives me

T(%)=97.27

Now, I’m wondering:

1. Is this direct conversion correct, or is there another step needed? For instance, should the transmission percentage be interpreted as 100−97.27=2.73% instead?
2. My main concern: using 97.27% as a tolerance in an MSA Type 1 study (to evaluate Cgk performance) seems illogical. Is there a standard or better approach for defining tolerance in such cases?

I’d appreciate any insights, corrections, or advice from those with experience in metrology or optical measurement. Thanks in advance!