H1B amendment requirement

[nivarp]

I am working for my current employer for last two years and my employer wants to change my salary after completion of two years of service as per the original contract. For first two years I was paid a fixed amount and now after the two years kick in I will come under productivity . So the total emoluments may go higher or lower ( not less than the original LCA approved minimum wages) depending on productivity . There is absolutely no change in contract terms,nature of duties, work location , employer or anything else for that matter. In this circumstances is there any need of filing amendment to my current H1B visa?

(Nivar)