Short answer: yes, you can reduce your 401k contributions to just enough to get the matching funds, without negatively impacting your plan.

Long answer: I'm in a very similar situation, though a few years farther along. Here's how I did the math.

Take your 2012 net expenses of 15k and inflate them forward to your projected retirement date. I used 3%. 3% growth on 15k for 10 years works out to about 20k in expenses in 2022 and 35k in expenses in 2040.

Your annuity pays 14k in 2040. Also figure social security at 10% replacement due to short working career for another 6k or so, total income in 2040 is 20k leaving a 15k/year shortfall in retirement. If you never add another penny to your current retirement assets, that 148k will grow to 552k in 2040 if they make an average of 5% annually, which would then provide you with 22k/year in additional income at 4% SWR, far more than the 15k/yr in additional income you will need. This means that you can survive returns lower than 5% before 2040, or you can draw less than 4% for your SWR in retirement, or you can inflate your standard or living and have a more luxurious retirement.

So the remaining problem is the intervening years between your retirement in 2022 and your annuity/SS/401k payments in 2040. That's 18 years of expenses you need to come up with at between 20k and 34k/year, or a total of about 440k in non-sheltered funds, and you've currently got about 43k invested. If you throw the additional 12k/year you have to invest into those accounts and make 5% returns, you'll hit about 205k in 2022, far less than the 440k in income you will need for that 18 year period. But it's not quite as dire as it seems, because your 205k will continue to earn interest for those 18 years, which at 5% is about 10k/year in investment returns, which means your 205k only drops by 10k in the first year (20k in expenses minus 10k in returns leaves 10k of principal withdrawal). In the next year, your remaining 195k will earn a little less than 10k, and your expenses will go up, so your balance will drop by 12k, and so on until you run out of money in 2034.

So you have a couple of options. You can do an early withdrawal from your 401k, which will be larger than quoted here if you continue to contribute enough to get the match, which I recommend. You can use your Roth principal contributions to float you for at least two or three years. You can save more than 12k/year in your taxable accounts at some point in the future. You can reduce your expenses further. Or you can do better than 5% ROI on your portfolio, which I think is likely over a 28 year time frame. If you make 7% in the markets, you're golden; you could retire even earlier.

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edited for clarity.