Only someone who has never raised a round could be surprised by this dynamic. Nobody wants to invest before there is a strong lead. And after there is, everyone wants to invest. Multiple tranches is simply the outcome of supply and demand. I think what @followthemani and @EricNewcomer misunderstand is that they presume there is some universally agreed upon price for any round and that somehow, the brand VC is getting a secret discount at the expense of everyone else. What it misses is just how unpopular a round can be, and just how close a round can be to failing, before there is a lead. @chetanp and @benchmark took a brave bet before it was obvious and derisked it for everyone else. All future investors were well aware of the round details and, so far, it turned out to be a great investment for all involved, as will be revealed next week!