I made bid manually for an item before installed or even had know about ebay snipping solutions.
I am higherbidder currently.

If I'll add snipe ot this item with myibay,
will it know that I'm higherbidder and don't even try to snipe if nobody will outbid me?

So snipping is not required if I'm already higherbidder by manually-placed bid.

Welcome to our forums.

It will try to snipe, but it will not outsnipe you if you use the same user id.

It will either:
1. Increase your maximum limit (without outsniping you) if your snipe is higher than your current.
2. Do nothing if your snipe is lower then your current or the same.

Okay.

Now I see that snipping don't bid, but just change my highest bid, so ebay using his "bid proxing" internalyy to choose a winner. That's why snipping can't outbid if you use the same account.

Thanks you.

You are absolutely right. That's how it works when you have your bid.