As a data point, the trip I am currently on (LHR/JFK return, Y>J SWUs both ways confirmed immediately after purchase as C inventory was available) was booked in April. (Now if you can plan ahead 6 months, currently there's a mid-week paid J fare of £1300, which is, to my mind, not too bad.)
My bugbear this year with AA is that on both previous bookings using SWUs the EQDs awarded were wrong, short-changed by about 30%. My guess is something about the ex-LHR tax co-payment upsets the EQD logic. I don't think it's related to $/£ since I've had non-SWU trips credited correctly. Both times it was corrected eventually following email prods to CS. It looks like it's happening again on this trip, but can't be sure till I've flown the return leg.