Battle Rating - Elven Hippogriff Cavalry?

I'm currently playing in a 5e campaign featuring epic battles. The DM is using his own rules for the large-scale battles, but I've been reading Domains at War lately and am trying to stat them out in ACKS - specifically using the Campaign Rules which requires BR factors.

Most of the troops are equivalent to types found in books, but we've got the "Sable Company Marines". They are described as hippogriff-mounted soldiers, the elite airborne cavalry of Korvosa. The riders are mixed human/elven/half-elven, but I'm going to treat them all as "elves" (the same as elven cataphract, but on hippogriffs instead of horses).

Using the calvary conversion rules from D@W Battles is straighforward at first, but I have a few questions...

1) I calculate the primary # of attacks primary for the riders' lances to be 60*(1+0.5)*(5.5)/180 = 2.75 (rounded to 3). But for the hippogriff, should I use...

  • the bite/hoof/hoof routine of 60*(3+0.85)*((3.5+3.5+5.5)/3))/180 = 5.35 (rounded to 5), or
  • the double-damage diving hoof/hoof attack 60*(2+.85)*((7+7)/2)/180 = 6.65 (rounded to 7)?

2) Do I apply the "flight" special ability (D@W battles p.94) as an additional BR modifier? Flight has already been factored in to a lot of the component factors, so it feels like double-counting. Without it, I get BR 28 for the 60 hippogriffs + elf riders. If I add the "flight factor" of 0.5, this ends up as (1+0.5)*28 = BR 42.