BUG: interface lacks enough bins in rare cases

[cicirello]

Describe the bug
In very rare cases, the interface doesn't include enough bins.

To Reproduce
Steps to reproduce the behavior:

1. Select instance number 412288.
2. Use any of the heuristic modes.
3. Observe that when you get to last item, 9 bins will be used, but last item won't fit in any of them.
4. There currently isn't a 10th bin.

Expected behavior
There should be enough bins for all items. Add a 10th bin to the interface.