Are you in Ontario? you could be seeing a difference due to the Trillium Benefit. You will need both to complete the Trillium Benefit that issues the benefit.
"While the Ontario Sales Tax Credit component of the Ontario Trillium Benefit is paid to the person whose return is assessed first, the Ontario Energy and Property Tax/Northern Ontario Energy Credit is paid to the person who has applied for the credit(s) by completing Form ON-BEN. The payment will be the same no matter who applies."
You can read more here: https://www.ontario.ca/page/ontario-trillium-benefit