I believe this is correct. Item based haste will always use the highest value (CoF & RBB equipped? You'll get the 36% from CoF only.
Bard songs are the same type of haste as shaman/enchanter hastes until the Erjav line with Velious.
If you wish to test it, get your hands on something REALLY slow. Like a
http://wiki.project1999.com/Weighted_Axe
Hit a few times with no haste. Log it. (/duel works really well for this)
Hit a few times with just Quickness from a lvl 20+ enchanter/shaman. Log it.
Hit a few times with just Verses of victory from a 50+ bard (should be same haste % as quickness). log it.
Hit a few times with both Quickness and Verses of Victory. Log it.
Should get the same delay between swings for each of the hasted tries. Use a level 1 to do the swinging so double attack doesnt screw with your numbers.
If you want, you can also do it with items (equip a FBSS only. Then a CoF only. then CoF + FBSS).