The intent of Scotus may be interpreted in three ways:
1)) That of Wolter which would make the distinction equivalent to a major virtual distinction (that of reason reasoned) and is thus unobjectionable. Voetius and Ames follow here (though for Voetius, see Beck 264n166). Thomas Ward follows here as well.
2)) That of Cross which would make the distinction equivalent to a minor real distinction. This would be objectionable. Burman and Alsted follow here.
3)) That of Grajewski in which the formal distinction ought to be thought of as standing on its own. Paulus Voet follows here.
The most I can say here is that Cross’s view is certainly incorrect.
Turretin’s comments on the distinction ought to be totally disregarded as he sees it as purely rational, that of the reason of the reasoner rather than the reason reasoned, which would not fit either or any interpretation of the formal distinction. I am quite unsure why he thought this.
Thanks to Jonathan Ramont who helped me fully organize my thoughts here.