what is the value of the asset? it's not just rental income, there are assets limits as well. if you are adding another property to your assets you may be impacted both by the asset and the income. your primary residence is not counted as an asset, but rental properties are

there is no magic formula. you need to fill in the module (mod R from memory) and it asks you to put in your income and expenses, and from that the annual income is derived. you need to provide a valuation of the property, you need to provide evidence of what you are paying on your mortgage (only the interest will be used as an "expense"), details of your RE if you are paying them fees, rates notices for water and land. it's not something that anyone on the phone can advise you of impact to payment, nor can anyone here, as each circumstance is assessed on it's merits