K27 as built and delivered

When the K27's were delivered they were of course
Vauclain Compound, and had slope back "switcher type" tenders. I know that BLW sold the compounds
for their efficiency and many RR's bought into the idea around that time. Many other RR's
converted to single expansion after trying the compounds.
But what would have convinced D&RGW to order slope back tenders? Surely the K27 wasn't intended to be primarily a switcher. The added visibility when backing surely wasn't worth the diminished capacities of the tenders, or was it?
I know that after all these years any answer would be at least partly conjecture, but does anyone have any ideas about this?