I've been getting mixed information regarding these buffs so posting here in hopes of getting this cleared up.

Long story short, two of my trusted friends who have played DAoC significantly longer than I have recommended that I don't use the Combat Speed and Combat Damage buffs together. In fact, they say it's better off just to use the Combat Damage one and ignore the Combat Speed one. Apparently, the Combat Speed buff doesn't work like it's described. As an example one friend stated how if you have two weapons with 16.5 DPS but one with a Speed of, say, 6 and the other 5, those speeds mess with the haste you're getting from the Combat Speed buff and you don't get the full, say, 39% increase. So even though the buff says Improves Combat Speed by 39% it actually doesn't, since the weapons move at different speeds. Also, somehow, by using both buffs together there is supposedly some algorithm where even though on paper you should be getting, for example, 25% melee damage increase and 39% haste, you don't. Somehow the numbers get dampened or something. When I asked why a) the buffs would say one thing and do another and b) why there would be such an algorithm in the first place they weren't exactly sure but speculated it's because using the two together would be too strong of a combination. My question to anyone reading this is:

Is any of this accurate at all? Please advise. Thank you.

16.5 weapons x 25% dps buff = 16.5 base dps x.25 = 4.125 = your bonus 25% dps

16.5 + 4.125 = 20.625 dps rounded to 20.6dps

swing speed(uthgard): weapon speed*(1-(quickness-60)/500)*(1-haste%+celerity%)

e.g. You're a troll, level 50, no quickness added at creation, no quickness in template, 39 sav. :: 58 base quick

[savage 32% haste//no healer celerity//58 quick no templated quick] 4.0*(1-(58-60)/500)*(1-32) = 2.7 swing speed
[savage 32% haste/31% healer celerity//58 quick no templated quick] 4.0*(1-(58-60)/500)*(1-32+31) = 1.5 swing speed [capped]

^ reason to not listen to your friend