ECM confusion

So a buddy of mine has a 1000. He kept blowing his EFI fuse.

He took a different friends ECM plugged it in a drove all day.

Here is where my confusion is. Some companies want $400 to flash the ECM Polaris dealership wants 1hr labor.

Some companies say the ECM comes blank and Polaris says it only needs your serial number flashed to it.

I think we’ve been getting screwed!

Any insight to this?