eyore, your link points to the generic one which is less sensitive. You can see on that Amazon web page that it is from the same manufacturer, MCM, as the link I posted.
The MCM telephone pickup does have the same overall shape as the Radio Shack pickup but the MCM pickup has lower quality parts & workmanship on the inside. I've opened both the Radio Shack and MCM pickups to fix broken wires (the cable gets pinched where it enters the pickup body).
The MCM pickup also does not have the rubber pads that the Radio Shack pickups do, to help isolate the induction coil and its metal core from mechanical vibration. If the speaker cabinet is vibrating at the right frequencies and the pickup is touching the cabinet, those vibrations will be transmitted to the coil as distortion.
So even if the incoming levels are well below clipping, the recording can have distortion. I think that's what happened with 772pilot's induction recording of "Disneyland Forever". Certain frequencies in "Kiss Goodnight" are distorted even though the levels are safely below 0 dB.
Another example are my induction recordings of the onboard audio for "Ghost Galaxy". I used a Radio Shack pickup that was firmly attached to the speaker so it wouldn't come off during the ride. SuperHotLarry could hear distortion in the very loud segments of the recorded audio and the speaker enclosure did noticeably vibrate during those sections.