Put 3 times your stable income in the emergency fund and reserve fund.
Do you really know what you are saying? had it been you said 3/4 of your discretionary income it could have sounded better than saying x3 of your stable income.
I think that he is trying to say to put three months of your income into an emergency fund and reserve fund, and sure there is likely a difference between emergency funds and reserve funds, since emergency fund might be a subcategory of reserve funds and would be the part that we would not want to spend absent any actual emergency. Reserve funds would potentially have more flexibility in terms of what they could be used for. Some guys do not distinguish between the two categories, yet I think that it can be quite helpful to have both categories in mind in order to be more precise in the various ways that we might manage our various kinds of extra cash (or back up funds).
Let me make it clear to you because i can see that you think emergency and reserved funds should be a fixed amount but if that's what you are trying to spell then you are wrong because it's from your discretionary income that you will scrap out emergency and reserved funds which means that each time you DCA, you will have to cut out some money and add it up to your existing emergency and reserved funds.
For me, your attempts to clarify matters seems to be making it less clear, since back up funds are built from discretionary funds, and once the emergency fund is built up, then it likely just stays in place, and it might get adjusted from time to time to make sure it covers expenses for 3 months... and back up funds are likely going to fluctuate in regards to how much back up funds are there, what they are there for and the extent to which they might get used up from time to time.. and then maybe needing to be replaced and/or built back up from discretionary funds.
Your DCA is likely coming directly from your emergency funds rather than from emergency funds or reserve funds, so you seem to be thinking about these matters differently if you think that DCA comes from either emergency funds or back up funds rather than from your discretionary funds that you establish on a fairly regular basis depending on when you are paid and when your expenses come due... For example, you might not know how much discretionary funds if you have some uncertainties in your income and/or in your expenses, yet when you get paid, you know how much you have available, but then if you have some uncertainty in the amount of your expenses, you might not know how much discretionary income you have at that point until you figure out your expenses. Sometimes your income might be so great that you know that you have discretionary income, even though you might not know the exact amount of your discretionary income until your expenses become known... so it could be that you choose to keep some of your income as float or even to keep it as reserve funds until the specifics of your expense amounts become known.
They are not fixed as they vary based on how much you can be able to make available after your DCA amount have been taken care of, any amount that is left can stand for emergency needs and as reserve funds.
I would suggest that income and expenses vary, so then that will affect your discretionary income. Sure, anyone who is confident that they are going to have discretionary income can choose to set their DCA amounts based on an assumption that they are going to have discretionary income, yet their creating those presumptions are not necessarily good practices if they end up presuming that they have more discretionary income than they have, and if they screw up their calculation of their discretionary income then they may well have to find funds from other places in order to cover their DCA and potentially also to cover their expenses.