We found we had a similar problem when we tried to change the Minimum charge, the new minimum was not being used, the Shipment Cost continued to be calculated using the old minimum value. We saw that when accessing the scale entries in TK12 the screen format had changed, where there was a row for MINIMUM that was had formerly not been displayed and the Minimum values was no longer displayed in a separate column (we are now running ECC 6.0 EHP 6, SP 14, we had previously been running ECC 6.0, EHP 6, SP 7).
With the newer version of TK12 we discovered that when you press the Scale icon for a Zone it displayed the scale data in a new format with a MIMIMUM row, we found if you F3 Exit back to the ALV grid and select the Scale icon again for the same Zone then it displayed the scale data in a format that showed the Minimum value for each rows (this is similar to how it was when we were running ECC 6.0 EHP 6 SP 7). On this second viewing of the Scale data you change the Minimum value on each of the rows and it uses that Minimum. It does not appear that a value entered in the MINIMUM row is actually used for anything, it instead needs to be entered on each of the rows on the scale.
I hope this helps.
Brad Kimpel