Give or Take - Which is Give and Which is Take

I was recently asked for a rough estimate on how long a small project will take. I figured it would be a couple weeks, most likely a bit less, but could also be a bit more depending on a few unknowns, so I said "It will probably be about 2 weeks, give or take a few days, most likely give."

I think I naturally went with "give" because it sounds more positive and less time on the project is better. But this logic doesn't hold up in situations where more time is better, like "I'm going to DisneyLand for 2 weeks, give or take a few days."

So which is it? Is the project giving time back? Or am I giving more time to the project?

Is the vacation taking more time? Or would you be giving it more time?

"give or take"

is a fixed (set) phrase that means...

approximately

Cambridge on-line defines it as ...

possibly a little more or less than the amount or time mentioned:

a little more or a little less compared to the amount mentioned

It is an idiom that indicates a range; trying to parse it is possibly a waste of time.

The general understanding is probably ambiguous, but I would parse it this way:
If the thing being modified by "give or take" is the time required for the project, then if I'm giving time to the project, it would take longer. If I'm taking time from the project it would be completed earlier.
Likewise with the time allocated for the vacation, I would be given a few more days or a few days would be taken from the vacation time.
Given how easy it is to misconstrue contracts and the conflicts that can arise, I would just be very explicit: "The project will take between 12 and 16 days" or "The project will be completed on or before March 31."