I think you failed to answer the op's question and they are being too nice to say so. Some games set a random 'seed' that do NOT reset if you quit and relaunch a game... so that quitting and reloading and doing something again will give you the SAME result every time (%s be damned...yes the %s are accurate but quitting and reloading will not give you 'additional chances', but will simply recalculate the last one).
In any case... quitting, reloading, and re-beating the boss fight CAN give you different loot drops, to answer what I THINK was your question was (If I'm wrong, feel free to tie my shoelaces between both shoes when I'm not looking then point and laugh when I fall on my face).
That said, I personally hate cheating in games but for things like this I have no shame in admitting I use cheat engine (albeit after beating the game once 'clean' first...so clean that I do not reload for new drops because I didn't know they even existed on a first playthru!) to just 'get' the drops I'm hoping to get from 1-time shot encounters that I would otherwise be willing to reload for, but only one...
that also said, blade cuisinart is not really a worthy boss drop to go thru so much trouble for. ordinary knight enemies in future floors drop them, and ordinary knight enemies appear in virtually every future floor, except the ones that drop better items like blue saber or scourge or whatever! the NEXT touhou girl boss on the other hand drops forbidden tablet, which IS a fairly difficult to obtain via ordinary means until far far later item, so maybe you should try to get hers =)
