Total Pressure Drop vs Equal Friction Duct Design

[dazataz]

All,
I dunno, I understand the newer Equal Friction method but dislike having to rely on introducing friction on the shortest runs with dampers/fittings for balancing.
I've slammed together a quick xls file and xlsx to look over what happens when I do what I understand was a "modified" way of doing Equal Friction.:
1) Review for longest Loop
2) Size that loop within FR and velocity limits
3) Obtain total PD of this Index (Longest Loop)
4) Match all other Branches to have nearly the same loss.

Playing around with the numbers in the spreadsheet, it's easy to see that going up or down just 1 size can louse up the Velocity and PD's quite a bit.

So, given the complexity of doing the analysis, and assuming most of you do not own fancy programs (we can't afford the $ or time to learn and won't hire a Mechanical Engineer for the one-off job we see every-so-often). Do you prefer the newer Equal Friction Method? From a designer's perspective, I prefer what I came up with in the spreadsheet (and we will still install dampers on each branch) - does this ring a bell with you all?

Disclosure, I am NO expect by a longshot ( : AND the data in the attached spreadsheet is basic but was obtained from various ACCA and other published texts.

BTW, is the newest Manual D much different than the 2007 version we have?
Thanks for looking!