Electronic structure calculations in p-type B delta-doped Si quantum wells are carried out self-consistently and within the Thomas-Fermi approximation. The self-consistent calculations assume both a two-independent (hh + lh) and a three independent (hh + lh + so) hole bands models. The numerically calculated spectra are compared between themselves and with experimental results, making emphasis on the effects of the inclusion of the so hole band. The Thomas-Fermi approach uses two different two-independent bands models: hh + lh and hh + so. Despite of the simplicity of this theory, comparison of the obtained results with experiments and self-consistent theoretical calculations gives very good agreements. Again, the influence of the split-off band is highlighted and the relevance of the approximations assumed is discussed.