I own two pairs of Gascans a crystal black/black iridium and a polished white/JIP. This morning I swapped the lenses. Removing the lenses from both pair was relatively easy, with perhaps the black pair being a little easier. Inserting the BI lenses is to the white frames was also easy. However, getting e JIP lenses into e black frames was considerably more difficult. Am I missing something? Now that they are in and seem secure is there going to be any harm leaving them in place? I should note that while they are bother the same model Gascan, the black pair is "Made in USA" versus no such text on the white pair. Hopefully it is just a variation in tolerances and no issue. Thanks.