By putting off the 401k contributions, you are essentially front loading your tax withholding, which earns you nothing. Also why are you putting your spouse IRA after taxable? Do you have Roth for yourself and traditional for your spouse? Why?
My way is probably not perfect, but I spread out my traditional 403b throughout the year. Any extra goes to my Roth IRA until full, then my spouse's Roth IRA, then taxable. My income and expenses tend to be lumpy so this gives me flexibility about how much to invest each month while still filling the tax advantaged buckets.
If you put your W4 with-holdings on auto-pilot, sure. If you have your expected tax liabilities figured out and set your with-holdings to be a fixed dollar amount the picture changes a little. Ideally you can estimate via spreedsheet far better than using the government form. I have never been a fan of getting a surprise at tax time myself.
Roth stuff gets taxed at 0% at some future date of withdrawal. Long term capital gains taxes on taxable accounts will also likely be very low if retiring modestly. 401k/IRA savings will have a higher marginal rate on withdrawal, say 10 or 15% (much higher if you account for ACA subsidy reductions as an effective tax).
So if you are putting equal total contributions into front loaded Roth and taxable into the first half the year, and 401k/IRA into the second half the year and average 7% returns, you will get crudely 3.5% more on average into the more exit-tax advantageous accounts than doing equal contributions to all accounts every month. It nets about 0.3-0.5% net after tax money in a horse race with no more taxes in the current years. Small, but not trivial. Likewise front-loading 401k/IRA, as was advocated a couple time, ends up 0.3-0.5% worse yet than equal split contributions, which is what got me thinking.
