Plunging shot weirdness - need help

Hello gents,

Was out at the levee shooting this afternoon (yes, I *finally* have a place to shoot), and just for giggles, decided to do some high-angle shots.

I don't have chrono equipment or anything like that, so what comes next is going to be weird.

I put out a target and shot the arrows up, trying to have them land on my target (a plastic bag with an arrow through it to keep it from blowing away). These were generic arrows with the typical freaking huge American fletchings, so they got all over the place by the wind, and my shooting isn't all that great to begin with.

But when, at about 80 paces, I tried to calculate the speed of the arrow, I waited to the stall point, and counted until they hit the ground. The average was almost exactly four seconds.

4s*32.5 ft/s^2 = 130 fps or 4s*9.8m/s^2 = 39.2m/s^2.

Now, I was shooting, again, ye olde typical wood arrow with a target point, which weighs, as close as I can tell on my wife's kitchen scale, about an ounce/437gr.

Now, here's the weird thing. I was shooting one of Grozer's "Scythian" bows (the "Sacytha" jobbie off his site is what he's calling it now)... but I specifically picked a bow that my wife and her girlfriend could shoot.

I know these bows are more efficient than longbows, and the the Turkish bow tests really get up there in speed... but 130 fps, from a 22lb bow?

Now, I realize that this ain't hitting with a lot of force (.028kg)*39.2m/s^2 = 1.1N ... but isn't that awfully fast for a bow *that* weak?

Can somebody help me out here?
tnx...