Comment by gamblor956

The accountants are not lying to you; you are misunderstanding what they are saying.

A single-member LLC and a single-member S-Corp are both essentially flow-through entities for a solo entrepreneur. However, they are ultimately taxed quite differently: with an S-Corp once you exceed the SSI threshold for the essentially mandatory portion of revenue you must repatriate to yourself as a salary, the remaining income can be repatriated as qualified dividend which is taxed at a significantly lower rate than directly passed-through income. With an LLC, it's all self-employment income subject to regular income taxation, meaning that in any realistic scenario, you're paying a higher effective tax rate with the solo LLC form.

So if I went the S Corp route, I'd actually have to pay taxes on 0 revenue.

This is false. The income tax on $0 revenue (meaning no revenue, not no profits) is the same: $0. (Note, however, that many states have "fees" assessed on business entities like S-Corps and LLCs, even single-member LLCs, and in such cases a minimum fee is owed regardless of revenue.)

But as a regular LLC, my own work (as the owner) does not count as anything taxable, so I'm safe.

This is also false. The work you provide to the entity as an owner is still an R&D expenditure. The difference is that with the S-Corp, the expenditure cost is clearly documented, while with the LLC you're pretending that the number is $0 and gambling on not getting audited. This only matters once you start generating revenue...

Either way, not all of your salary would be subject to capitalization. If you have revenue, you clearly spent at least some time and work on marketing and business development, and expenses for those non-R&D activities are not capitalized.

With the S-Corp, your salary offsets up to [your salary assigned to non-R&D tasks less 1/10 [see note] of your current-year salary assigned to R&D plus carried-over capitalization from R&D from prior years] in revenue each year, and after an appropriate amount of salary (generally the SSI contribution threshold for the year) the rest of that annual revenue can be repatriated to yourself as a dividend at lower tax rates. With the LLC form, since you aren't paying yourself a salary, you owe tax on 100% of the revenue arising from the software you develop without any deductions.

TLDR: If you actually care about tax, S-Corps are almost always the better option for the solo entrepreneur, and they're still the better option here.

NOTE: Capitalization is on a mid-year convention, so the first and last year you only capitalize 1/10th of the cost; and in the middle 4 years you capitalize 1/5th of the cost. So, for Y2, if you paid yourself $100 in salary both years, your total capitalization deduction would be $30: $10 capitalization for the Y2 salary and $20 for Y1 capitalization.