Non-Diminution of Benefit

I've read online that the principle of non-diminution of benefits states that "any benefit and supplement being enjoyed by employees cannot be reduced, diminished, discontinued or eliminated by the employer."

 I've googled this kind of info since there is an issue at the office wherein the drop off points of our shuttle service will be removed. Instead everybody will just be service up to the gate of EPZA. I am not sure though if this can be considered a diminution of the said "benefit" since it is not on our contract. It is existing for I would say 4-5 years but still not on our contract. I will be greatly affected by this decision and definitely there is nothing I can do. Anyways, its not the end of the world, I want to be positive and hope to find the light at the end of the tunnel. I wonder how long this tunnel is, hehe.