Do you really want to use that formula every time you want to get a drive potential?
No.
I'd rather use
THIS (if it's not too much trouble).
The formula would be a lot more complicated than the table, so why would we want to?
Depends on "how you build the formula" I guess.
You can do it the "maximum complexity/Rube Goldberg" way that you have ...
Or you can do it the "simple division" way that
I have (as have others before me) ...
It would not give us any more information, such as the potential of a C drive in a 150 Dt hull.
When all you have is a "table of answers" with NO FORMULA for how those answers are determined/validated ... then the table is "all you've got to work with" and there are NO OTHER ANSWERS AVAILABLE for intermediate tonnages (such as Drive-C @ 150 tons, as you cite).
When you DO HAVE A FORMULA for how those answers in your table are determined/validated ... then you CAN find additional answers that are NOT IN THE TABLE for intermediate tonnages (such as Drive-C @ 150 tons). The table becomes a "partial list of quick reference" rather than an "exclusive list of only possibilities" when you know (and can use) the formula "behind the curtain" that, in effect, made the table take the form that it does.
It's a bit like the difference between arithmetic and algebra.
Algebra tends to be a lot more flexible and useful than arithmetic.
That's because you can use algebra to do the work or arithmetic ... but you can't use arithmetic to do the work that algebra does.
Arithmetic "works" for what it does, but algebra is a much more powerful and expansive paradigm to work with for doing math.
1+2=3 gives you a single answer for a single case.
x+
y=
z gives you ALL THE ANSWERS for ALL THE CASES ... just plug the values into the variables and you can find your answers.
The LBB2.81, p22 drive tables (both of them) are Prematurely Optimized for the page layout format they are presented in. The only way you can make use of the information is ... arithmetic. Which makes sense, because in 1977 and 1981, pocket calculators were only just starting to become consumer items that were reasonably priced for household use (so you didn't need to use Slide Rules or an Abacus for calculating numbers quickly).
Nowadays, we've got calculators in desktop, laptop, tablet, handheld phone and wristwatch form factors (among others), so we don't need the kind of training wheels/hand holding protection against seeing formulas that we did when LBB2 was first being edited into existence for publication in 1977 (and updated in 1981). We can handle "easy math" such as knowing that a Drive-C has 600 tons of "performance rating" so that in a 150 ton hull form factor it will yield USP code: 4.
X /
Y =
Z
Drive (performance, in tons) / Hull (size, in tons) = USP code (drop fractions to integer, only values of 1-6 allowed)
Simply include the Drive (performance, in tons) rating for each letter drive as part of the Drive Potentials table of information ... and it's just a matter of simple division from there to arrive at an answer for ANY combination of letter drive and hull tonnage, including all the intermediate tonnages which are not shown on the table. The table becomes a "convenient point of reference" for lookup of SOME possibilities ... rather than a "controlling tyrant" that denies the existence of ALL possibilities other than what is explicitly shown (including errors in multiple table entries).
Do you really want to use that formula every time you want to get a drive potential?
Your formula is even more cumbersome to use than the LBB2.81, p22 table, to the point of being Rube Goldberg-ish ... so ... NO.
The reason behind why your formula is so cumbersome and Rube Goldberg-ish is actually an indictment AGAINST the LBB2.81, p22 table as published ... rather than a supporting argument for it ... in my view.
