Vive la difference.

I couldn't say if the crop is any heavier, but there are differences.
1. Sown "this year" they would reach 2-3' or more, then start to flower, then get attacked by black-fly.
2. Sown "back-end" last year they survived handsomely, flowered & set seed early and low down - then reached full height unattacked.
Top shot, typical habit - back-end sowing.
Lower shot - about 1/2 this years crop.