Well if you think that will get you through the course waketurb you might as well ask for it.
New joiners are bonded from the skill test. Has been that way for decades. Those that don't make it through the course are asked to leave, and no money is taken from them.
The Skill test happens a bit over a month to two months before the end of the course, and its timing is a Known, as there are no roster restrictions to slow it down. If you would like to have the bond started after the initial line check, you have employed yourself with EK one to two months extra than as it will stand now.
Be careful what you wish for.