Me too. I like round and even. 300 for a blade you like, sounds "off". 400 sounds much better. Besides, here, many blades aren't a good deal at all, price wise (namely all the Rapiras and the Gillettes except for Astra). So, since i decided with delay to buy from Ebay, i may as well grab the Rapiras in a "decent" number.
Besides, blades aren't supposed to go bad, availability locally isn't go to increase, reformulation (i hate the new Astras without ink, thank God i purchased 1200 of the old ones) or cessation of production can happen and prices aren't go to decrease. As a matter of fact, the main local shop from which i purchased the big part of my blades, has 2 months ago, increased all prices by about 3-4 euros per 100 carton. If you think that i bought 50 cartons, i saved about 150-200 EUR for having purchased before the price hikes.
As Gillette continues to penetrate the chinese and indian markets with her cartidges, production of DE blades will inevitably slow down and prices will increase. And availability will probably do the same. Shark Super Chrome are impossible to find here for several months now. They were available when i started wetshaving, but disappeared for good. Dorco Primes were available at Amazon, now they still are but with 2-5 weeks delivery.