This isn't quite right. To be a base rate entity, there are two tests:
(a) aggregated turnover must be less than the threshold (presently $50m); and
(b) 80% or less of assessable income must be base rate passive income.
So, in response to the original question, if base rate passive income exceeds 80%, the entity is no longer entitled to the 25% tax rate. The 30% tax rate will apply :-(
See:
https://www.ato.gov.au/tax-rates-and-codes/company-tax-rate-changes#Baserateentitycompanytaxrate1
Thanks, brain fade, meant to say 80% passive or less than 20% active. Overall principle is it's good if you get to pay tax at 25% while the company is earning its business income then frank at 30% when dribbling it out of the company when they are retired