i've seen termsheets of callable accreting notional swaps where the accretion rate equals the fixed coupon rate. apparently these are used to hedge callable zcb's. but it doesnt seem to make sense! the fixed leg of the swap is paying coupons, whereas the zcb doesnt pay coupons. i guess maybe it is done like that to reduce credit risk. and then the question is , should the funding leg of the swap also have accreting notional? that seems a bit strange too.
Also, i am trying to think if the callable swap should have a call fee on it or not (and if so, what exactly), as for the callable zcb , there must be a call fee equal to the accrued notional (that is the equivalent of par for a zcb).