Can remapping a Mercedes turbo diesel engine cause damage?

I have remapped the engines on 15 of my Mercedes Sprinter 515 for better fuel economy.In the last year I have had to replace 7 of the engines in these vehicles. Can remapping cause big end bearing or con rod damage to an engine? I also suspect the company that services my vehicles has used the wrong oil in the past. Could that also contribute to engine failure? Thanks.