I, too, would have the old insulation removed. You'll need some gloves and a mask but it's CHEAP to guy. Of course, do wear long clothes and buy LOTS of plastic 'refuse' (not trash) bags. YOu know, the type for yard waste. They should be at least 1.75mil in thickness.
In addition to what Steve: said, the old insulation under the NEW insulation is 'useless' from the sounds of it. Also, there will be large air gaps (relatively speaking) which is NOT what you want. Think of it this way. Batt Insulation works by trapping and HOLDING the warm air inbetween the fiberglass fibers. By preventing the movement of air (by trapping it in a sense), you've created insulation. WHen insulation is compressed, you've LOST that feature. And by just 'covering up' the old insulation, you've prevented the insulation from being RIGHT UP AGAINST the living space where it does its job BEST. So, in short, it would save you MORE $$$ by having the OLD insulation removed. Remember, lay the Kraft-side DOWN on the attic floor.
As an aside, I don't know why you're adding chutes if you're not insulating the roof (ie., between the roof rafters.) WHen you do what you're describing, usually one is finishing off an attic to make the space liveable. The chutes prevent the roof insulation from preventing air from rising up to the ridge vent. Again, if you have soffit vents, after you've removed the OLD insulation and AFTER you've layed down the NEW Batt Insulation, as 'bc' said, just make sure your NEW insulation doesn't cover the vents. Maybe I'm off on all this. Perhaps 'others' can agree/disagree more??!
My best to ya and hope this helps.
Jay J -Moderator
PS: IF what you ULTIMATELY want to do is insulate the attic AND use it for storage where it's an UNFINISHED, UNHEATED 'space' where you can lay down some 'flooring', more needs to be considered. In short, whatever you end up doing, you DON"T want to seriously overly-compress the new insulation with plywood sheets and planks! In doing this, as others have said, you'll decrease the R-value of your insulation. There are ways to 'raise' the attic floor so you can install sheets and planks W/O deminishing the R-value of your insulation. Others on the Forum can expand on this (please).