For years the STANDARD length on a 2ply roll of Blue Centre Feed has been 150m. So for a case of 6 x 150m you would receive 900m in total. BUT more & more manufacturers & distributors are now selling 120m & even 110m rolls
So for a case of 6 x 120m you will receive 720m in total. 180m LESS than the standard 900m. So you are losing out on more than a full roll.
They are manufactured to look the same. They are wound more loosely on the core. Some manufacturers even avoid putting the length of the roll on the packaging & instead will state the amount of sheets on a roll & perhaps the length in cm of each sheet, leaving you to calculate the total length. So be aware. If the price looks too good to be true & the length is not stated, then it probably is too good to be true