Your search ignores their medians. The below charts are all for GPAs above Penn's median GPA, all I did was change the LSAT:
Below median LSAT, above median GPA:
Median LSAT, above median GPA:
171 (75th) to 175, above median GPA:
176 to 180, above median GPA:
Your chances improve between these two charts when you increase your LSAT score past Penn's medians with the GPA held constant. There's a slight drop at 176 to 180, but it's very small and could be due to small sample size and variation.
Same series, but with the GPA below median and still held constant:
Below median LSAT, below median GPA:
Median LSAT, below median GPA:
171 (75th) to 175, below median GPA:
176 to 180, below median GPA:
Same thing here. There's a slight drop at 176 to 180, but again the sample size is pretty small. Perhaps there is a tiny amount of YP going on at the 176-180 range but I'm not convinced of it. The sample size is too small to make any real conclusions about that group. If there was YP going on, it would also seem to affect the 171+ people who are CCN and HS candidates.
Based on these charts, when you increase your LSAT, with the GPA held constant, your chances generally improve. This doesn't indicate YP. However, when you compare the first set of charts with the second set, you will see how much lower your chances are when you are below the GPA median. This is what I think is causing people to think it's YP, because it seems crazy that Penn would WL a 175, but my guess is the majority of those WL people had below-median GPAs.
I think Penn just doesn't care how far you are past their medians once you hit them. It also seems like they are weighting GPA higher than some other schools in the T6, which is why they would take a 170/3.88 and wait-list a 175/3.6. This is what makes this year seem even worse, because now that the median is a 169, there are many more median GPAs that are now median LSATs that Penn can choose from.