If I change from 2 part time jobs to one full time, will it better my chances for mortgage?

My fiancé an I went to a mortgage lender 3-4 months ago and he let us know that only the income from ONE of his two part time jobs would be counter towards qualifying for a mortgage, because he just recently acquired his second job (even though he s had his first job for 5 years and they re both in the same field). At his second job he s already been promoted and received a raise and might be willing to just offer full time.

If we want to be able to apply for a mortgage in January 2016, would it be a good idea for him to quit his first job and just have one full time position with his most recent employer? Or will it count as him only having that position for 7months? (It will be 10 months in January). Should he just stay with the two part times until after we buy a home?

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