98.51 or 99.49 can be rounded to 99, but not 99.0, which can be rounded from 98.951 to 99.049. If they say 99.0 or 99.1 or 99.2, then it wasn’t rounded up from 98.7. I think that’s right.
Wasn't putting any micron rating to the rounding up example, as already stated. The example is what I think companies do to get the 99 on their box. Some are at 20, some are at 30 etc. some may be at 40. The magic is to get the 99 on the box so people buy it. The asterisk and small micron number are hidden enough so many people won’t see it. So they buy it. The company exists to sell the products.
The word absolute means 100%, but some call it 98.7%. Absolute is absolute not almost absolute. So by the 100% I believe the micron rating is excellent. Another way I think it’s excellent is I think 27 is an excellent number, more than Supertech or some others.
Excellent doesn’t mean best, but to me it means, excellent. So many variations on that one word. Even most excellent. Baldwin could say their filters are
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So maybe it’s correct or not but that’s my answer to your questions.