Your GP tax is so far off, I have no clue what you are using to calculate it. Are you including the cash that they get from the KMP and KMR units that KMI owns. Keep in mind, logically, the GP take can never exceed 50% of all the cash produced by the MLP, because the highest tier of the incentive distribution rights is 50%. The lower tiers are less than 50% which brigns the total take down. Now, if you add in the cash they get from the LP units, the total Take (not tax) can exceed 50%. XTXI takes about 75% of all cash produced by XTEX, but that is because they own 10 million of the 26 million XTEX units outstanding. I highly suggest you look at your GP tax model. You are clearly a smart guy as evidenced by your knowledge of splits, GP MLP relationship etc, if you look hard enough, you will see, that the tax can never be more than 50%, it isn't mathematically possible, ever, unless you distort the definition of GP Tax to be GP Take.
KMI's IDR is $.55 for KMP's $.79 distro. The GP splits cannot exceed 50%, but if they would take 50% of everything it would be a 100% tax by my definition of the term. We discussed the term definition in an earlier posting.