When I first started exploring LTC policies, I was going to do the same thing. Then I took a closer look at the way things would actually work, and noticed that the additional coverage I'd be buying later would all be at higher (sometimes a LOT higher) rates for individuals of that attained age. So, for example, if I'm 45 YO, my $25 per month premium is buying me $150/day in benefits. I decide to buy additional insurance every 2 years to make up for the erosion of benefits due to inflation, I'd eventually be buying this additional insurance coverage at the rate they charge every other 75 year old--which is very expensive.
Your approach is not totally without merit, but be sure you look ahead and crunch the numbers. Because of the higher cost for insurance for an oldster, your premiums will be going up a lot faster than the rate of inflation. If you are serious about keeping the policy until you need it, I think you'll find it is cheaper to buy the inflation protection at the outset.
Also, (as I mentioned previously, sorry to hit this again) be sure to buy a policy that qualifies for your state's LTC Insurance Partnership program. This is a big deal. The salesman will tell you it isn't important--that's because he wants to sell you a different policy. The Partnership-qualified policies provide you a benefit that is paid for by your state--if you get a policy that doesn't qualify, it's like turning away free money.