I’ll be sure to post updates.
It was disappointing that the online application asked about the presence of foreign pensions but did not ask about value. I know from using the SS site to estimate pensions after WEP that my 2 private pensions take me to the max WEP, adding OAP did not change anything so I don’t see that there should be any need for an interview by a UK staff member.
But, I have applied 3 months before my 70th birthday so it may work out okay time-wise.
I remember when I was interviewed I was asked about other pensions, but not about the amount. There is a form I had to fill in later, documenting other pensions when that time came (when I started receiving them) ... Form SSA-308 Modified Benefit Formula Questionnaire — Foreign Pension, in case you haven't been asked to complete it as part of your online application - if not, might be worth completing and sending to FBU now so it's already on file. It can be pretty complicated, and I had to type up an addendum because there was so much additional detail of the following periods:
Section 3: Periods of employment or self-employment on which the [other] pension is based. Provide specific dates.
Section 4: Periods of employment or self-employment from item 3 above used to determine your pension which was after 1956 and which was not covered by US Social Security. Provide specific dates.
Section 5: Specific periods of voluntary contributions or other non-employment based credits included in the computation of your pension.
I also had to include the "award letter" for my UK state pension - I presume a similar evidence would be needed for whatever other pension you might need to include.
You say you will be maximally WEP'ed ... could be worth messaging FBU to ask, can you voluntarily accept maximal WEP without having to provide all the additional information. Logically, it should be neither here nor there to them, but with governmental agencies, you never know. Worth getting all this documentation all ready just in case.