I wonder if there's some confusion going on here. The OP should have been filing Schedule C and SE all along anyway, and putting his music expenses on the Schedule C, not using the Employee Business Expenses section on the 1040.
The now axed Employee Business Expenses were for wage earners, known as W2 earners. Any qualified personal expenditures related to your W2 employment could be entered, and there was a formula to deduct a certain percentage of those costs over a certain threshold. If that is what the OP was doing, he should go back and re-do the past three years of returns and put those expenses on Schedule C for a full offset against his 1099 income. The OP will have to pay self-employment taxes (if he wasn't), but that amount will be credited towards his future social security income.
If you're a gigging musician, your 1099 income should be put on a Schedule C, whether you are set up as a business or not. If you have the music set up as a business, it's easier to track and accumulate more legitimate expenses to offset that income. You have access to the home office deduction if you're a business as well. Even if a particular job was for less than $600 and you didn't get a 1099, you are still obligated to report it.
Pay attention to Schedule SE as well. Self employment taxes need to be paid on what's still showing as income after all expenses are deducted.
Perhaps the OP's accountant was doing that all along and the OP didn't really know what was going on under the hood.
One of the reason we see so many employment agencies, and companies now hiring staff only through those agencies, is there was so much unreported self-employment tax going on when a company would hire a freelancer or independent contractor direct. it was a real mess that resulted in much confusion on who was an employee and who was an independent contractor, and companies got caught in the middle, some having to cough up FICA payments as a result. Now, most large companies only hire through a staffing firm to insure someone is paying those self employment taxes. In the case of a staffing firm, the freelancer is now an employee of the staffing firm. That sucks for lots of freelancers as many lost their independent contractor status and can no longer use the home office deduction or other types of business expenses as many have been reclassified as employees of the staffing firm and are now W2 earners.
It really is important to see a CPA to make sure everything is working in your favor so you pay only your legally required amount of taxes, not more, not less. For example, if you are set up as a business and take credit cards, and the bar owners pays your band after the gig with his company credit card, you swipe his card with your Square device on your cell phone, etc, you may get a different type of 1099.
It can get complicated, so please see a CPA.
Also, as an individual, you have to decide how you want to roll. A bar you play for may pay you in cash. A company you play at for their corporate event will issue you a 1099 if the fee was over $600. And maybe even if the amount is under. And there will be no 1099 required to issued by anyone when you play at a quinceanera or wedding unless an event planner is hiring and paying everybody. Then you will probably get one.
It can get complicated, so please see a CPA.
This. Coolhandjjl is correct. I'm a tax accountant, and way better at that than playing bass.
