Some questions about pool mining

So I am sort of a noob at this, I had a couple of questions that I wanted to ask. 1- do shares/min matter for example my average shares per minute at the moment are 0.384 (I recently changed pools) previously I think I was getting somewhere around 0.7? I am not sure, I didn’t notice it before. But I feel like I have been submitting less shares because there were a lot of notifications regarding each submitted share in trex

2- that previous pool was a small one, it had been 4 days since the pool found a block last time. But the current payout was somewhere around 21RVNS, how is it possible that on 30mh/s and for 3-4 days of work my estimate is this figure? Where as this new pool finds a block every 2 hours I believe. Is that good?

3- if your rig gets switched off before the pool finds a block, does that mean whatever effort you put into the pool for finding that particular block is wasted?

Thank you.