By other words, if some issue (item) of the book title is available (free), the patron has to go to the checkout desk and to ask this free item. No remote order is allowed in this case . The hold (order) is allowed only if all items are checked out and patron must wait until some item is returned.
There are two preferences influencing the Koha holds function: On shelf holds allowed = NO, Item level holds= Don't allow. It is adjustable in Administration › Circulation and fine rules for patron category. Now it works incorrectly in such manner that holds are enabled if one or more item is checked out, but on the shelf remains some free item. It should not to be enabled, until all items are checked out (no free item).
You are correct in that this is how shelf holds work in Koha currently. If on shelf holds are not allowed, only one item need be checked out to allow a hold to be placed. You want the inverse where one available item disallow holds on the record
This problem was investigated in bug 6837, see http://bugs.koha-community. org/bugzilla3/show_bug.cgi?id=6873, the problem
was resolved by Barry Cannon, see Attachment http://bugs.koha-community. org/bugzilla3/attachment.cgi?id=23162&action=diff,
but this attachment is without approval (failed QA).
You could contact the original author to see if he would update the patch, or you could hire a Koha developer to do so.
My message is, that this problem is not satisfactory solved until now.
Koha is always changing. The best way to make Koha work for you is to advocate for the features you need! If we as a community don't hear that something doesn't work for your situation, it will never change! I think this email is a good start! Kyle