Mandos... addictive li'l things, ain't they??
About your "backward" tuners...
As you hold the mando upright and look at the back of the headstock, most of today's Pacific Rim mandos (as is your Washburn)will have their tuning machine gears oriented with the worm gear on TOP if the ring gear at each string post. "Vintage" mandos and today's upper-end mandos usually had the worm gear located BELOW the ring gear. Most quality replacement tuning machines that you buy today are of the vintage variety... my guess is that the machines you took off had the worm gears on TOP and the ones yoy put back on had 'em on the BOTTOM. The way the gears are usually cut, this would have the effect of reversing the tuning action you've been used to.
BTW - about your trade - I once traded a tenor banjo for a six-pack of Schlitz and a bag of pork rinds... even THAT was a good deal on my part! You did well, my friend!
"Ah, but I was so much older then, I'm younger than that now." -Bob Dylan