I don't read anything that says the pay freeze applies to movements through the levels. I'm happy to stand corrected.
So, the way I read clause 16.7, it applies post-2014, so any LAME on Level 13 or below will progress to the next level on service points during the life of the agreement.
The lower the level, the higher the percentage pay rise.
Worst case, for a Level 13 LAME progressing to Level 14, that's a 4.5% increase regardless of the year of increase, and in addition to the 3% + 3% + "1.5%". For all levels below Level 13, the percentage increase is higher - up to 7.4% for a Level 1 LAME.
Food for thought...