Belgium Blue card and Permanent Residency

Hello,

I am working in Belgium for more than 4 months and traveled on Blue card issued in the name of the organization.

I am interested to continue work and live in Europe and I have following queries;

1. If I have to work for an other client other than the name printed on my blue card then what is the process to get the name change for new client. How long does it take in processing the name change? Do i have to go back to my native country during processing?

2. If i work in any other EU country for  based on project requirement during my 5 years of stay in EU, will my stay years will be counted against applying for permanent residency in Belgium?

Is there any expert who can guide me better please?