Absolutely. I know everything I know from following the posts of the guys you quote above

The first of Myhrg's formulas is the unmodified chance of a unique version being dropped. As you see, it involves (mlvl-qlvl) in a necessary way. The other numbers come from itemratio.txt, a fairly simple file.

The next line is just application of the adjusted MF you calculate in your existing calculator.

The final line is the cap applying. If your MF is enough to bring your chance below the cap (also found in itemratio.txt), it will be set to the cap. Because both MF and (mlvl-qlvl) are used to work out your MF chance, you can't work out exactly where the cap applies without the (mlvl-qlvl) info.

There is a further step after that. Certain monsters have bonuses to dropping and these apply now (after the cap). All monsters have a value "cu" found in TreasureClassEx.txt. For most monsters (regular rmonsters) this field is blank, or 0. For Champs, Uniques and SUs, it is 800. For bosses it is 983 for their normal drop but higher for their quest drop. There are also special cases. It is used like this:

unique chance = "final" unique chance - ("final" unique chance * cu / 1024)

That is essentially chance * (1024 - cu) / 1024, but we write it the way we do to make sure you get rounding correct - D2 only uses integers, after any division you should round down.

Now, all these "chances" are actually the denominator of fractions like this: 128/x

The 128 factor is added in Myhrg's first formula and is so that we can keep some accuracy using only integers. The final test is to take a random integer up to "unique chance", and if it is less than 128, it is a unique.

If it is not a unique, exactly the same logic applies for sets, then rares, then magic. Of course, you have to remember to include the chance the item is not a higher quality first (so for example, actual chance(set) = (1 - chance(unique)) * chance(set).

Ah, just realised there is a typo in Myhrg's first formula - I recall he worked out the error later in the thread he posted it in - it should be:

unique base chance = (ItemRatio[Unique] - ((mlvl - qlvl) / ItemRatio[UniqueDivisor])) * 128

It doesn't really make sense the way he wrote it.