Using the ounces and pounds analogy you proposed:
1 lb = 16 ounces
An equivalent 4lb to 7lb tolerance in ounces would be a factor of 16 in ounces so we get 64 ounces to 112 ounces.
Using the AMS2430 3.11.1 UOS rule, the scale we are using (ounces or lbs) does not matter when using the 30% rule. 30% increase is 30% increase so scaling works regardless.
4 lbs x 30% = 1.2 lbs so we get a tolerance using the 30% rule of - 4 lbs to 5.2 lbs (64 ounces to 83.2 ounces)
64 ounces x 30% = 19.2 ounces so we get a tolerance using the 30% rule of - 64 ounces to 83.2 ounces (4 lbs to 5.2 lbs)
These are equivalent tolerance ranges when we use the 30% portion of the rule.
But when AMS2430 3.11.1 says “or .003” whichever is greater” the .003” should specify what scale you are allowing the increase in, A or N, because they are both measured in inches. The .003 should not be applied without this consideration. In our analogy we would have to say “ or 3 lbs whichever is greater” then we could equate 3 lbs to ounces scale as 48 ounces and use 48 ounces to base our decision for the application of the 30% instead:
4 lbs x 30% = 1.2 lbs - 1.2 lbs is less than 3 lbs so our increase defaults to the 3lb addition and becomes 4lbs to 7lbs
64 ounces X 30% = 19.2 ounces - 19.2 ounces is less than 48 ounces (3lbs) so our increase defaults to plus 48 ounces and becomes 64 ounces to 112 ounces.
Because both the A scale and N scale are measured in inches the scaling factor of 3 seems to be getting forgotten in the spec.
