Perhaps I'm missing something really obvious here, but is it the case that you have to renew at 3,000 Tier Points every year to benefit from that reduced threshold?

In other words, it's not possible to do the 'renewing every second' year trick by getting all your Tier Points just after each alternate membership year end during your 'grace period' - unless you were to get 5000 Tier Points every second year?

Obviously with the grace period soon being only a month, earning even 3000 TPs would be hard enough.