The contract gives wages, not increase in wages. It does not say you receive a $2.35 raise.
If you say you lose the $.70 raise because you don't get another $2.35, then you do lose it, but if you are say you have to pay back the $.70 when you get to the next level, then you are wrong. The money you are paying back is from your seniority date thru Apr 18, 2014, which you should not have received.