The difference is that on many (most?) lathes the graduations are for diameter – so a movement of say .25″ or mm, will result in a change in diameter of .25. The actual tool movement will be .125.
On the Myford the graduations refer to cross-slide movement – or a reduction in radius. So we have to divide by 2 and set the .125 directly.
Correct cycloidal profile achieved – unless the addendum has been adjusted to allow a slight clearance and prevent bottoming which would jam both pinions. The dedendum +F, will certainly be slightly overdeep – and it is the space, not the tooth that is being cut!
In which case you can expect a slightly “blunt” tipped tooth. Ivan Laws book Gears and Gear Cutting pp30/31certainly shows that, and the fact that a correctly cut gear engages only on the flanks of the teeth.
All these modules and DPs etc have all been carefully worked out, and it would be wisest I suspect to do it to drawing!. The reason for that is that your gears will not maintain constant velocity if the PCDs of the two pinions do not touch. By changing the depth of cut you will alter the PCD of each pinion slightly.
One of the advantages of involute gears!