[en] It has been shown that notwithstanding the separability of the Schroedinger equation for the Lo-Surdo_stark (LS-S) problem for hydrogen, the quasistationary states cannot be always characterized by parabolic quantum numbers of n₁, n₂,m. It is a reason why any numerical procedure of the calculation of the LS-S parameters E₀ and Γ which ignores this circumstance can appear to be invalid for large values of n₁ and F and small ones of n₂ and m. Experimental data on the photoionization of atoms in the presence of an electric field in the vicinity of the Rydberg series limit E=0 are in an accord with theoretical predictions. 32 refs.; 6 figs