Okies, just checked and the outcome is probably the reverse of what may have been feared - the pool has actually paid out for more blocks than have been found. Since the start, 320 blocks have been paid (at the time I started writing this post) but we've only actually found 316 blocks (at the time I started writing this post). In other words the pool has been 4 blocks too generous to members.
I'm not sure why this has happened. We did get a lot of dust spam when the dustpamming happened a few weeks ago. This may have glitched things (hopefully just temporarily). The wallet is quite large as a result of the spam (156 Megabytes) so I'll have to keep an eye on things to check that the pool doesn't get over-generous again.
The long block itself (132,797 shares) could have been a slight statistical anomaly. Based on current difficulty, the average number of shares in a block should be approximately 18,057. If my recall of basic mathematical probability is correct, this would mean that probability (p) of not finding a block in 1 share would be 1-(1/18057) , ie 0.99994461981503018220080855070056
Therefore probability of not finding a block in 132797 shares = 0.99994461981503018220080855070056 ^ 132797,
which is 1/1563.2559503291552340608534314844
Seeing as we've found 316 blocks (at the time I started writing this post) we can take this further and say the probability of this
not happening in 1 block = 1-(1/1563.2559503291552340608534314844)
which = 0.99936030948752221763835994466282
Therefore the probability of it not happening in our 316 blocks = 0.99936030948752221763835994466282 ^ 316 , which = 0.81692590176193059890347301959426
So the probability of it having happened = 1- 0.81692590176193059890347301959426
which = 0.18307409823806940109652698040574 , or 1 in 5.4622691556268153974020504585354
Therefore although it was quite a horribly long block, the probability of it happening in our 316 blocks so far is not as hugely-wildly unlikely may seem.
If I've got any of the mathematics wrong by the way, please feel free to correct me anyone