Only recently started using this product. I used to use the multi techniques version but I do a lot or freehand painting & use foil & clingfilm to keep the product moist.. however, I seem to only be able to achieve a a level 7/8 lift on hair, I've used it on 3 clients, one with virgin hair, one with coloured hair level 4 and one with coloured hair level 6. Has anybody got any advice on this product please?