I think that this is a bit misleading. Sure, the difference CAN be less than $1000... the rare time that economy is getting full and business is wide open.

In real life the difference is several thousand dollars each way most of the time. The OP posted earnings from a year with VERY low PQD (great P fare SFO-IAH, by the way!) so he is clearly taking advantage of flexible dates and flying when economy fares are low (or is very, very lucky). There is no $1000 buy-up to business in his future.