If you are talking about MQL VPS for MT4/MT5 so no additional activations needed - this information from MQL5 Rules -
Products purchased at the Market do not require additional activation for working in the Virtual terminal. The number of a purchased Product's available activations is not decreased.
Forum on trading, automated trading systems and testing trading strategies
MQL5 Virtual Hosting hosting and EA activations.
Marco vd Heijden, 2017.01.18 14:41
No if you migrate the terminal it will create a copy and use the same Experts already loaded.
Please see:
https://www.mql5.com/en/vps/tutorial
Note that this relates to MetaQuotes VPS so not standard VPS in that case yes you will lose more activations and since they are bound to the system you activate them on they will be lost when you try to switch servers or providers etc.

- www.mql5.com
if 2 vps in same company need 2 activation
and the activation according to what , if pc formatted I will lose it