The scalar-tensor theory of gravitation proposed by Mbelek and Lachièze-Rey has been shown to lead to a possible explanation of the forces measured in asymmetric resonant microwave cavities. However, in the derivation of the equations from the action principle some inconsistencies were observed, like the need no to vary the electromagnetic invariant in a scalar source term. Also, the forces obtained were too high, in view of reconsideration of the experiments originally reported and of newly published results. In the present work the equations are re-derived using the full variation of the action, and also the constant of the theory re-evaluated employing the condition that no anomalous gravitational effects are produced by the earth's magnetic field. It is shown that the equations originally employed were correct, and that the newly evaluated constant gives the correct magnitude for the forces recently reported

The scalar-tensor (ST) gravitational theory of Mbelek and Lachièze-Rey (MLR), allows electromagnetic (EM) fields to modify the space-time metric far more strongly than predicted by General Relativity and standard ST theories.
The theory was applied in cosmological and galactic contexts, and it was used to explain the discordant measurements of Newton gravitational constant as due to the effect of the earth's magnetic field. It was further shown that a ST theory of the MLR type could explain the unusual forces on asymmetric resonant cavities reported at that time. However, in the derivation of the equations from the action principle some inconsistencies were observed, and also the forces obtained, after reconsideration of the experiments originally reported and new results were too high.