Plus flag applications, in the majority of cases, will be guaranteed an offer at the minimum entry requirement. If a degree has an interview, test or portfolio requirement you will be guaranteed progression to that stage of the admissions process.
You need to read the widening access more carefully. Ds asked these questions to admissions staff directly.
This means if you are going to be given an offer, after your application had been reviewed, you are guaranteed the offer will be at the minimum entry requirement. Not everyone with widening access is "guaranteed an offer".
Also you are guaranteed to get an interview, not you progress past it.