[etoir]

I think there are some misunderstandings here:

First of all, when the GP says "you are more likely to be in a slow block", it means "you are more likely to be in a slow block, relative to how many blocks there are".

In your example, if you pick a block at random, you have 1/21 chance of being in a slow block. If you pick a block by choosing a moment in time at random, you have 1/3 chance.

It is obviously not true that with any distribution you would be absolutely more likely to be a slower block.

Secondly, your last sentence seems to give a reason which doesn't fully make sense, and certainly isn't 'the opposite' of the given reason. Slow blocks of course have longer average wait-times than fast blocks. But this affects both the 'time-weighted' average and the 'block-weighted' average.

If you think that slow blocks have a longer wait-time than fast blocks, but that slow blocks are less likely than fast blocks (in the time-weighted average), shouldn't that make the time-weighted average LOWER?

[gowld]

Splitting a long block into two shorter (but still long) blocks doesn't make you less likely to be in the covered interval, but does reduce the average weight time.