Your assumption is incorrect.
Wrong again. Solo flight training is flight training.
Mmmmm, whaaaaaaaat? ...the FAA actually defines that phrase:
From the "definitions" bit of Part 61:
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Flight training means that training, other than ground training, received from an authorized instructor in flight in an aircraft.
Ground training means that training, other than flight training, received from an authorized instructor.
...
Training time means training received -
(i) In flight from an authorized instructor;
(ii) On the ground from an authorized instructor; or
(iii) In a flight simulator or flight training device from an authorized instructor.
-------... and then there's this bit:
Logging training time.
(1) A person may log training time when that person receives training from an authorized instructor in an aircraft, full flight simulator, flight training device, or aviation training device.
(2) The training time must be logged in a logbook and must:
(i) Be endorsed in a legible manner by the authorized instructor; and
(ii) Include a description of the training given, the length of the training lesson, and the authorized instructor's signature, certificate number, and certificate expiration date.
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...now, part 61 does phrase things sometimes confusingly like: "(for PPL) 40 hours of flight time that includes at least 20 hours of flight training from an authorized instructor and 10 hours of solo flight training in the areas of operation listed...", ...so is it these particular phrasings that you're talking about? In which case, this would seem a highly unusual interpretation of the FAR's. Outside of a few odd (and perhaps poorly-chosen) phrases here and there in the Private/Sport Pilot section, when the FAR's talk about "flight training" they're talking about the CFI-y type defined in 61.1, for which 500 hours of burger-runs (no CFI, no logbook-signing) does not count.
...At least in Part 61. Maybe there is some weird corner of Part 141 that I'm not versed in...? In which case, feel free to school me, as I don't really know Part 141 at all.
I don't think the OP's question or
@Clip4's take is stupid or absurd at all. "Flight experience" and "Flight training" are two different things to the FAA. So the OP needs to know if the "25% transfer thing" applies to one, or the other, or both.