A rep for the estate confirms to TMZ that they've filed legal docs in their ongoing dispute with Katherine Jackson over attorney's fees that she's trying to have the estate cover ... over a deal that the estate itself struck, which she's currently appealing.

TMZ has seen the paperwork ... and it lays out some financial info that, if accurate, is absolutely eye-popping.

In the filing, the estate claims there's a massive amount of cash and other benefits Katherine has received since Michael's death in 2009 ... with the executors of the estate alleging it all totals more than $55 million over the nearly 15 years.

A good chunk of that dough, the estate claims, comes in the form of a monthly allowance it says Katherine is afforded by MJ's estate, and totals more than $160k/month.

that allowance -- plus other cash payments -- amount to $33 million of the $55m total, according to the estate.

On top of that, the docs say Katherine is well taken care of by the estate ... which claims to have shelled out more than $15 million to buy and improve her luxury home, not to mention paying for her transportation and other perks -- like a private gardener, chef, and security.

The point of the estate executors laying this all out is to bolster their argument Katherine can afford to cover her own attorney's fees as she pushes forward with her appeal to fight a huge business deal the estate struck ... which she and Michael's son, Blanket, were fighting together until recently.

Unclear what exactly that deal is, but it appears to be related to the blockbuster deal the estate struck for Sony to buy half of MJ's music catalog for 9 figures.

We broke the story ... Blanket filed legal docs earlier this week that made clear he, too, felt Katherine should be covering her own attorney's fees for the appeal -- and that the estate shouldn't have to pick up the tab.

Blanket was on Katherine's side up until a judge ultimately ruled against them, and he decided it didn't make sense to go forward with an appeal of that ruling.

Blanket now says he wants out of the fight -- and that Katherine is on her own for the appeal.