Is it crazy to expand a subnet then exclude a range for another subnet?

My situation:

I have two sites, one of which uses 10.254.98.0/24, the other uses 10.254.99.0/24. At both sites my pool of available IPs is very limited and I need more.

Both sites have a lot of 3rd party devices and tunnels and whatnot set up, doing things the right way is going to be very problematic right now - maybe 12-18 months down the road I'd be able to get all of the planning put together and cajole all of the vendors to get all of their ducks in a row. For the moment I'm looking for a quick and simple hack to give me the additional IPs that I need for client PCs.

I've been planning to buy some edge routers and subnet off the various zones then somebody suggested that at my second site I change the 10.254.99.0/16 to a /20 and exclude 10.254.97.1-10.254.98.254 from the DHCP scope, then change the other site to /22 and exclude 96.1-96.254 and 99.1-99.254

I've never heard of such a thing, never considered it, never thought about it. Aside from being an inelegant kludge is there a reason why this wouldn't work, at least as a temporary patch until I can properly redesign and re-implement everything? My first reaction was that this was nuts and would never work, but the guy was insistent that it could be done so now I'm doubting my initial reaction.

edit: Screwed up the CIDR notation. Hopefully it is correct now before anybody noticed.