To be eligible under PGP Sponsorship, income for 2017,2018,2019 will be required. if Sponsor's income for 2017 is $ 250 shortage than eligibility income, but they exceed income requirements for 2018, 2019, can they be eligible for sponsor their parents with promise to take financially responsibility of their parents? if income shortage is less , is there any way out by submitting letter of Explanation or affidavit to convince the visa officer about income requirements