Unless my math is wrong your hash rate as a percent of the pool's is 0.0000345%
And your shares (at 32 shares per shift) as a percent of the pool's is 0.0000352%
So at 32 shares per shift with 0.5GH/s, your getting right about what you should.
Regarding it flipflopping between 32 and 64 shares per shift, look at how small of a percent your hashing (or shares) are to the rest of the pools and it's easy to see why it's hard to calculate that exactly.
I have a couple GH/s at CEX,io and my results jump around a little also, but by the math I'm never getting short changed and that's what counts.
Thanks for the fast reply.
My other question would be why my stats always say the 32/64 shares found all of a sudden, shouldn't it be counting in 1s? Like you found 1 share, and another, and another, It shouldn't be starting out as 32 shares found.