Does the position stamps have been stuck to an envelope reduce orincrease it's value?

I would like to know whether the way stamps have been stuck to an envelope give different values to the cover?
That is if the stamp/s have been stuck to the top right corner gives more value to the envelope compared to having been stuck to the top left corner or bottom right/left corner or even stuck on various places such on top & bottom of envelope or even on other side of the envelope.

The reason I am asking this is I found at a local post office in my country (Mauritius), the proper place to stick stamps are to the top right corner.
But I have seen numerous( majority) of used envelopes I have obtained from companies mail have the stamps stuck haphazardly ( in any place what ever, top , bottom, middle, & both on front & back )

So I am wondering whether it is better to cut off stamps from such envelopes or leave them on for added value.

Thanks for your help in advance