There is a potential ambiguity as to what should happen when you step by a “day”. Should it be a 24 hour period, or should it be a calendar day locked to local clock time? The latter is usually 24 hours, but might also be 23 or 25 hours or even something different again, depending on whether daylight savings changes take place on that day, and how much daylight savings adjustment there is.

When you step the chart in Astro Gold by a day, this is implemented as step of 24 elapsed hours, rather than a calendar day. It would be possible to implement the alternative method if people have a particular need for it, but note that you can still adjust for this manually by stepping the chart back or forth by an additional hour if you wish.