Might be a modification (adjusted spring tensions) or could be failed hardware at the mounting pivot, but the angle is appropriate to the smaller freewheel as long as the tips of the pully teeth don't rumble against the biggest freewheel cog (and the chain doesn't sag) at any time.
More chain wrap equals more continuous power transmission under load, esp. during shifting.

I have hot-rodded various PX10 Simplex derailers to give more chain wrap around different sizes of freewheels, usually by increasing the "A" pivot spring tension, and it always helps with power transmission during hard shifting.
Using ball-bearing pulleys allows increased chain tensioning with virtually no increase in frictional power losses, and if the original ball bearing pulleys are cracked, I substitute Huret ball-bearing pulleys adjusted with Gr25 1/8" ball bearings.

You have to be careful when messing with a sprung Simplex mounting pivot though, because turning the mounting bolt with a 6mm Allen wrench will shear the bolt away from the tensioning plate fitted with flats on the other end, and then it's difficult to get enough tension into that spring!