So Verizon cannot charge for tethering on 4G service, this raises the question of whether they can continue to charge for tethering on 3G or 1x?
Your answer lies in those "narrow exceptions".
Its a regulation on the bandwidth block used for 4g. not the range for 3g. different frequencies, different rules.
U X e dUdX, e dX, cosine, secant, tangent, sine, 3.14159...