In tm0, the total charge of the nucleus is +2e and the total charge of the electrons is -2e. In tmA, the total charge of the nucleus stays the same, but the total charge of the electrons changes to -2e – ε. This introduces extra negative charge into the problem, lowering the energy of the charge configuration.
When using an electric charge -e + ε/2 for a single electron in tmA, the energy could be above that of tm0.