Mortgage/Tax Question For a 1099 Realtor - Advise Needed!

[Adrian Peterson]

My wife is looking to refinance a property she purchased more than 6 months ago. She is a CA Real Estate agent and receives a 1099 for her commissions. in 2018, she deducted a large write-off so that to avoid paying high taxable income. Consequently, the tax returns now show low income as a result of the write-off, thus disqualifying her from being approved for her refi.

Should our taxes have been structured differently? If so, please advise. Thanks!