[GNC] Confused About Budgeting monthly transfers

[Jon Griffith]

I'm a first time user of gnucash and I've run into a challenge that I can't
figure out.

Preface:  My budget is a plan.  My budget is a zero based budget, meaning
that I start with the income I'm expecting, and I "spend" all of it until
nothing is left every month.  Part of that "spending" is transferring $$
into savings, which is a net zero Income/Expense transaction.

Hypothetical:  Every month I receive $3000 net.  I need to "spend" 15% of
that by moving it to my Roth IRA.  So, I transfer $450.00 to my IRA from my
Checking account (Liquid to Non-liquid asset transfer).

I would figure that on my Budget, I could enter $450.00 as a value for the
IRA asset account and it would be subtracted from the total at the bottom
of the budget in the "transfer" row thereby reducing what I have left to
spend for that month.

Problem:  Some asset accounts affect the transfer value on the budget and
some don't.

I understand how to do a transfer from a register, but "planning" for that
transfer such that it affects the budget bottom line seems to be spotty.
What am I missing?