Sorry for getting the old thread back.
I think there is dynamic price (uncertainty) for renewal some premium ngtld. I try to register more than 1 year for a premium name. But the registrar doesn't allow it. I contact them, they reply this:
Sorry, but we do not know the renewal price. Registries for nTLDs can charge anything they like. We think this is a very confusing system, but it is the one they have elected to use. Most premium nTLDs renew at the same price as registration, but not all. we do not know what their pricing will be.
Thanks,
NameSilo support
Registrar said it all. If anyone can shed the light from trusted source..