word usage - Choosing between up and above in this context?

I have always been confused about the use of above and up. Lets say I in grocery store and I am supposed to describe the position of X in a high rack.

Should I say "It is 3 shelves up and in the back/front (of that shelf)." or "It is 5 shelves above and in the front."?

Can anyone please explain to me which is correct and why?

Answer

I think you could say

It is 3 rows up and in the back/front.

although there should be some reference as to up from where, unless you are looking at that row. You could say

It is 3 rows up from the middle shelf, and in the back/front.

In the case of

It is 5 rows above and in the front.

you have to specify above what. In this case you would not use above by itself. You could say

It is 5 rows above the vanilla ice cream and in the front.

Also, in a grocery store, it is more likely to say shelves rather than rows.