I've just read the 'Move Chargers' section again (BRB pg 20) and it clearly states that if the charge range was sufficient (meaning the distance measured between the two closest points of the two units involved has to be equal to or less than M + 2D6") then the charging unit can move an unlimited amount. It goes on to say "That said, the charge move is subject to one important restriction: the unit must move straight ahead, expect that, during its move, it may make a single wheel of up to 90°." To me that's more than clear enough; if you're close enough, than move the units into BtB with one wheel of max 90°, for which you do not need to pay.
The charge move is resolved exactly as Wolf has indicated - you just measure the straightest line distance between the units and ignore the wheeling distance. The charge rules could be better written to make this a little clearer but Wolf has definitely hit the high points. The issue is resolved 100% on page 14 with the last sentence of the wheeling para where it specifically states, "You don't need to measure the distance wheeled by a charging unit,..." Measuring the charge wheel is yet another 7th ed holdover that I have had to ween myself away from
You don't even have to measure the distance via a valid path! As long as the two units are no further apart at their closest point than the rolled charge distance AND there is a valid path i.e. one with no more than a single 90 degree wheel then the charge is successful. The remaining questons are about how to line up the units not whether they should be lined up.