I have observed that over time, saline filled implants that are overfilled, will .... relax. It makes sense; the tension of the implant shell releases a bit after the (over)fill. It is for this reason - that while overfilled saline implants can give exceptional projection (actually shrinking in diameter initially as they project outward) with initial extreme overfilling, they ultimately release a bit. I'm not talking about the lady's skin stretching, but the actual implant. Also, this only seems to apply to implants - not expanders which may have a thicker shell.
I think that's the reason why Tammy Hernande looks so exceptionally large even though it's been published that she's only 2500cc's. Her 2500's look closer to 3500 or even 4k. I realize that she's actually quite slim/petite which helps with the (dis)proportion that we all love so much. But nevertheless, those look huuuuge. Pandora Peaks enjoyed the same incredible coverage of her chest, with her 2500cc implants. I believe that this is the reason why.
In many images, Tammy appears larger than Mary Madison, who is published as being notably larger. I feel that it is because of this reason.