The screw sizes refer to the length of the shaft, not the diameter of the head or socket. P5 is the standard pentalobe size for all these screws, regardless of length.
I agree that the notation is a little confusing. I think it's because, with standard sized hardware like for your house, you have shaft diameter (say 1/8" or 3mm) and shaft length (say 3" or 7.5cm). So we're programmed to think of small numbers like that as diameter. But in this case, they're length.
The screw sizes refer to the length of the shaft, not the diameter of the head or socket. P5 is the standard pentalobe size for all these screws, regardless of length.
I agree that the notation is a little confusing. I think it's because, with standard sized hardware like for your house, you have shaft diameter (say 1/8" or 3mm) and shaft length (say 3" or 7.5cm). So we're programmed to think of small numbers like that as diameter. But in this case, they're length.