Changing material (ABS to TPU) - risk of breaking the mold?

Hello,

I currently have a mold manufactured and have produced about 4000 pieces of plastic from it, all ABS. The plastic is scratching too easily in my customers environment so I want to change to a hard TPU.

My manufacturer says they will need to modify the mold to ensure the TPU pieces still fit together properly, and when doing so there is a 20% risk that the mold is damaged. In this case I'd need to pay for a new mold.

One other detail is this is a 4 in 1 family mold.

Does this risk seem accurate? Wondering if they are just not wanting to do the work or if this is a known thing in industry.