Don't think so...the minor ticks values are hidden in HG with no way to access them. I suppose one could save the figure as an image and find the pixels that are set and deduce it from that but is pretty tough.
The best think one could do would be to try to work out heuristically how many minor ticks there will be based on the major tick spacing; by default it starts with five, if you increase the spacing as you did above in the example there are 10; if decrease by spacing at 0.5 for major then there's only 2. (These are divisions between major divisions, not the intermediate ticks). But I don't think there's any way to retrieve what is done internally.
ADDENDUM Oh, in digging following up Kevin's response I see there is a recent enhancement...but must have R2015b or later to gain access to it.
