Well, the partition coefficient is a measure the distribution of a compound between two solutions. If you have compound X between solvents Y and Z, LogP is an expression of the ratio of [X] in Y vs [X] in Z. It is essentially telling you which solvent (Y or Z) the compound X is more soluble in, and how much more (or less) soluble X is in Y compared to Z.
LogP does not affect lipophilicity, it is a measurement. If you measure the length of a piece of string you do not affect the length of said piece of string.
So if you have:
Compound A partitioned between octanol and water and it has a logP(oct/wat) of 0
Compound B has logP 1
Compound C has logP -1
can you rank them in order of lipophilicity?