I've had this toothbrush for 1 year. I have an important question about the functions of the brush. Does anyone know if the 4 modes ("clean.white+.gum.health.deep.clean") really change anything if you use them with the same head? Or are they only useful if you have all the heads corresponding to the mode? I'll illustrate my question: I have W2 (optimal.white) and C3 (plaque.defence) heads. Is there any point in varying the brushing modes? Should I stay on .white+. with the W2 and on .clean. with the C3? Will the brush brush differently if I put the W2 head on the .deep.clean. mode, or should I just put it on the .white+. mode? And the .gum.health. mode, will it change the brushing done by the W2 and C3 heads, or would it only be useful if I had a G3 (gume.care) head??? It seems to me that this is an important subject, but I haven't found any information yet!