AGASA energy spectrum and the GZK cut-off

We discuss primary CR energy estimations for very large surface EAS experiments. We show that the procedure of energy determination via the relation to particle densities at 600 m from the shower axis, rho(600), requires a specific treatment for inclined cascades when the maximum of GAS development is close to the array. As follows from simulations and cascade theory, using an exponential function for rho(600) conversion froth inclined to vertical showers is no longer valid and leads to all overestimate of the primary energy. We present a procedure to reconstruct the primary spectrum that can reduce the discrepancy between the results of fluorescence experiments and surface arrays.