Well, I can institute something like an "invalid block insurance" at 3% "fee"... I hesitate to call it a donation, though, since a donation implies of someones free will. But like a couple pools have done in the past, they insure against invalid blocks with a forced donation of x amount. I'm certainly open to this if there's enough demand.
1) Didn't I read something about the scoring system leading to some (much less than normal) pay on invalid blocks? Was that the previous scoring system, is the block chart wrong, or is the calculation wrong?
2) How do the averages work with invalid blocks? Technically, doesn't "44% luck" on an invalid block equate to no luck, and shouldn't the average luck percentage (if not the next block luck percentage) include the time wasted on the invalid block but not the luck from it (avg divide by 49 instead of 50 or something)?
Nope, there's no less than normal pay on invalid blocks, unless you mean 0 pay? As much as I'd like to pay out on invalid blocks, I can't afford to pay 50 BTC out of my pocket. I'm not really making money on running the pool and my Ferrari is sadly still on layaway. Actually, I'll settle for an Lotus Exige or Ariel Atom at this point.
I'm not sure I understand your question with regards to the block chart being wrong?
As far as the averages, there's a few different ways you can look at an invalid block and each are equally valid but produce very different results. The convention, perhaps set by Deepbit and Slush et al in the beginning is to acknowledge invalid blocks as being a separate legitimate entity. From a purely continuity standpoint, this should not be so and invalid blocks should never be acknowledged as existing in the first place as far as pools go - thus they should just be passed over and the current block continues as normal.
Convention and technical limitations make this more difficult in so far as it takes time for a block to be realized as invalid, so unless the pool delays the stats, an invalid block shows up in the chart until it's invalidated by the network.
So, as far as luck goes for both the invalid and current block, since it's acknowledged as a separate entity from the current block, it takes with it it's luck. It's ultimately a semantics game, and through convention and technical limitations, you get what you see. If people would prefer another method/display/semantic convention, I am happy to oblige, I just chose the current method because that's what people are already familiar with and I am definitely not trying to hide anything.
I would like to point out, with this latest invalid, we are right under the "average" as far as invalids go, since the start of the pool (400 blocks * 1.5% = 6 invalids).