Breaking the 4 piece Tier 9 bonus

Having only just ground out enough heroics to earn 4 pieces of the Tier 9 Enhancement set, I now find myself with emblems of Frost and a couple of lucky drops. Unfortunately these are in the shoulder and chest slots I've currently got filled with Tier 9, so to equip them would mean bye bye 4 piece T9 bonus. But is this bad?

To find out, I used Rawr and Enhsim together to simulate my current DPS, then in Rawr I swapped out the chest and shoulder pieces, exported into Enhsim and reran the simulation. See this post for more details.

current gear, 4pcT9 bonus - 4768 dps
current gear, 2pcT9 bonus - 4666 dps
current gear, no bonus - 4610 dps
new gear, 2pcT9 bonus - 4747 dps

This is not so good. To equip those two new pieces, and put epic attack power gems in them, will result in an overall DPS loss of 21 DPS. We can see that for my gear, the 4 piece Tier 9 bonus accounts for 102 DPS alone. This is a very disappointing result, and means those items will most likely rot in my bank :( Even if I got another i251 item for legs or hands and dropped to no Tier 9 bonus, the item would need to give an extra 56 DPS to make up for the loss of the 2 piece Tier 9 bonus, THEN to match the stats of the i232 item I had, THEN to give more DPS to warrant the effort of gemming and enchanting. This also seems unlikely.

How about the 2 cheap bits of Tier 10, the gloves and shoulders, stuffed with expertise gems and enchants to try to make up the loss of 52 expertise rating from the gloves (ouch)?

2pcT10 & 2pcT9 bonus - 4820 dps

So dropping the 4 piece Tier 9 bonus to replace it with 2 piece Tier 10 & Tier 9 seems to be the way forward, giving 52 DPS increase plus more if I re-gem for expertise. I guess the chest piece will not rot forever, if I make my Tier 10 bits shoulders, gloves, helm and legs then I can use that chest instead of a Tier 10 one.

TLDR: I won't be breaking 4pcT9 unless it's for 2pcT10 2pcT9.