We calculate the strongly intensive variables sigma and Delta that suppress trivial volume fluctuations and are constructed for the charged particle multiplicity n and the total transverse momentum P-t in a modified multipomeron exchange approach for proton-proton interactions in the range of collision energies attainable with the SPS and LHC accelerators. In this approach, the interaction between the color quark-gluon strings formed from cut pomerons are effectively taken into account; in this case, the role of these interactions increases as the collision energy increases. The inequalities sigma(P-t, n) > 1 and Delta(P-t, n) <1, which agree with the experimental data, are the main result of the calculations for energies attainable at the SPS. We show that as the energy increases, sigma(P-t, n) behaves nonmonotonically and Delta(P-t, n) increases.