I only have a couple domains at namecheap, but maybe this question applies to all registrars. If I renew all my domains to the ICANN max of 10 years, can they

I only have a couple domains at namecheap, but maybe this question applies to all registrars. If I renew all my domains to the ICANN max of 10 years, can they retroactively charge me for time paid if the price increases? Some may note that some registrars allow for more than 10 years, but that assumes the registrar remains solvent, as the max is 10 years.