System wiring reconfiguration - thoughts?

The way my system was originally designed (schematic #1) was to have a combiner box closer to the inverter, but that means that all the string positive and negative leads had to make their way from the panels on opposite ends of the roof over to that location. That meant either 5 x 10AWG conductors going from the upper right side of the roof, through a J-Box or pass-through, down through conduit in the attic, then popping back up on the upper left side and into the combiner box. Total would mean 6 x 10AWG conductors total through the conduit.

Cost wise I figure -

20ft x 5 conductors, so 120ft of 10AWG THWN-2 wire: $50
20ft x 1 conductor, 10AWG USE-2: $10
20ft x 2 conductors, 40 ft total of 6AWG (from the combiner to the inverter): $20
Pass-through box: $95
Polaris wire connectors: $35
Total: $200




So I got to thinking, why can't this be simplified? It would be less total wire to run through conduit, plus a pass-through box wouldn't be needed.
The way I figure it -

40ft x 2 conductors, 80 ft of 6AWG THWN-2 (from the combiner to the inverter): $40
20ft x 2 conductors, 40ft of of 10AWG USE-2: $20
Total: $60






So not only is it a cost savings, but it seems like a lot simpler install. Less parts (no pass-through needed), less wire. Thoughts?