Error with number of slice and plots

[Delino-WKB]

There are some bugs in the displayed options for times and slices.
Some options shown are not really available for plotting, other options are not shown and cannot be plotted even though they should be.

For example, in this case, I ran a sumulation with one slice with four step irradiation history.
These are the options I expect to have available for plotting:

tugui gives me a different set of options not compatible with the simulation I ran:

Note that in tugui options there is a second slice that does not really exist.
Note that in tugui options there are two times missing for plotting (10h and 949h).

If I plot a set of value really available i get a resulting plot as it should be:

[dmanzione]

The solution suggested by @lelaus for checking the ISLICE value has been included. The same logic proposed for ISLICE has been applied to the check on the ISTATI flag, as well.