Question on scanning 35mm slides --

Note: I'm using a Canon CanoScan 8400F with slide scan accessory. Printer is a HP DeskJet 5150.

Ok, here's the situation:

I scanned a slide at 1200 and at 2400, which produced images that are (A) 1596x1080 and (B) 3192x2172. Then I cropped a similar section out of A & B, and had images (C) 366x280 and (D) 732x560.

Next, I printed each one at about 6.8"x5.3" on photo paper. The detail in each looks the same. Why isn't the print from image D crisper and clearer?