Lets see, If you cut to say 10% BF then youd be 140 lb at 5'10 (giving you a BMI of almost exactly 20). If I remember rightly a BMI of less than twenty is considered under weight (not that BMI is accurate for fat percentage determination for body builders but it does give an indication of size).
The point is at 10%BF and 140lb you'd be lean but as other posters have said youd also be lacking in the way of having much muscle mass.
In fact at 140lb your weight (according to most weight charts) would be on a par with what would is considered appropriate for a small framed female at your height (albeit the female would be around 16% BF as opposed to your 10%). Seriously though I can give a link to a site showing that the ideal weight for a SMALL FRAMED female at 5'10 is 132 to 145lb and the ideal weight for a small framed male at that height is 144lb to 154lb.
Im not saying that to be rude or anything just pointing out that your current weight is not one where you need to be concerned about being too big not even too fat - Im trying to make the point that you need to be worried about weight gain at this point not weight loss. Im actually half wandering if you might not have a bit of an anorexia mentality going on? (I can remember being 145lb at 5 ft 9 when I began body building at age 19 myself and thinking how big my muscles were but in hindsight I was actually at a weight that was no bigger than appropriate for a healthy female at my height, albeit at 9% BF I was somewhat leaner).
So what would be the point of cutting then? Obviously not to show of your physique.
The only other reason you might cut is if you thought it might speed up the rate at which you acquire lean mass in the long run. As fat converts (aromatizes I think the word is) the big T into estrogen there is an advantage in losing fat before bulking for some people (for example middle aged people who are 230lb at 16% BF like myself will benefit from cutting before bulking due to the increased T levels that will potentially result from doing so - which is why in my case I am now cutting).
However because you are young and should have high T levels (and with abdominal fat destroying T not such a problem at your age) and because your total fat isn't that bad (if I had your total body fat I'd be under 10% BF) I personally doubt there is much advantage to you cutting before bulking right now (in terms of raising your T levels).
Really I just think you need to concentrate on bulking for now (and I suspect that youve possibly already lost too much lean mass from your previous dieting and if you continue in your intended case of action you likely will lose even more lean mass).
Point is at your height and weight if you lose 6 lb or more you will be at a weight that is considered too low for even a small framed sedentary male so it sounds like you have a serious lack of lean body mass going on i.e. low for a body builder but probably normal for a small framed sedentery male; so cutting is the last thing you should be looking at doing; yet you are looking at doing just that, like I said could there be some anorexia type issue going on here?