Honestly, based on what I did with this film in HC-110, that sounds long to me, though I do not claim to have tried this combination myself. Scala was a very contrasty emulsion with a high maximum density; characeristics that are fitting for a film designed for reversal, but give you a "difficult" film good for nothing but special purposes as a neg. I used it only in very flat light, such as overcast landscapes. If it helps at all, I rated it at 100 as a neg and developed in HC-110 dilution H (an unofficial dilution that is twice as dilute as dilution B) for five to eight minutes, depending on the contrast I wanted. Even at five and six minutes in that highly dilute developer, I still got contrasty negatives. (However, this is exactly why I chose to use the film in the first place: to inject a very flat scene with a healthy shot of contrast.) If I had not used it solely to shoot in flat light, I probably would have applied even more EC by rating it at 50 or 25, and really have gone to lengths to pull the emulsion. It is up to you, but I would just hold the film for situations in which you want a very high contrast black and white negative film.