are expected to be paid in cash. We expect the plan to generate expense savings of at least $50 million in 2020 and approximately $100 million in 2021. The foregoing figures are our estimates and are subject to change.
For the three and nine months ended September 30, 2020, we incurred $9.1 million and $24.8 million, respectively, of expenses related to this plan. For the three and nine months ended September 30, 2020, $0.8 million and $2.5 million, respectively, are included within Cost of services and $8.3 million and $22.3 million, respectively, are included within Selling, general, and administrative in the Condensed Consolidated Statements of Income. For the three and nine months ended September 30, 2019, we incurred $91.5 million and $98.9 million, respectively, of expenses related to this plan. For the three and nine months ended September 30, 2019, $33.9 million is included within Cost of services, and $57.6 million and $65.0 million, respectively, are included within Selling, general, and administrative in the Condensed Consolidated Statements of Income. Refer to Part I, Item 1, Financial Statements, Note 5, Restructuring-Related Expenses for further discussion.
These expenses are specific to this initiative; however, the types of expenses related to this initiative are similar to expenses that we have previously incurred and can reasonably be expected to incur in the future.
Cost of Services
Cost of services primarily consists of agent commissions, which represented approximately 60% of total cost of services for both the three and nine months ended September 30, 2020. Cost of services decreased for the three and nine months ended September 30, 2020 compared to the corresponding periods in the prior year due to a decrease in agent commissions in our Consumer-to-Consumer money transfer business, which generally vary with revenues, including due to fluctuations in the exchange rate between the United States dollar and foreign currencies, a decrease in restructuring-related expenses, and a decrease in employee-related expenses, including as a result of reduced hiring, partially offset by an increase in credit losses. For the nine months ended September 30, 2020 when compared to the corresponding period in the prior year, the decrease in Cost of services was also due to the Speedpay divestiture during the second quarter of 2019.
Selling, General, and Administrative
Selling, general, and administrative expenses decreased for the three and nine months ended September 30, 2020 compared to the corresponding periods in the prior year due to decreases in employee-related expenses, including incentive compensation and as a result of reduced hiring and savings from our restructuring plan, and a decrease in restructuring-related expenses. In addition, for the nine months ended September 30, 2020, Selling, general, and administrative expenses also decreased due to reduced marketing costs and decreases in costs related to strategic initiatives, including for the review and closing of mergers, acquisitions, and divestitures, partially offset by the strengthening of the United States dollar against foreign currencies.
Total Other Income/Expense, Net
Total other income/expense, net during the nine months ended September 30, 2019 was impacted by the non-recurring gain on the sale of our United States based electronic bill payments business known as Speedpay. In addition, total other income/expense, net during the three and nine months ended September 30, 2020 compared to the corresponding periods in the prior year benefited from a reduction in interest expense driven by a lower weighted-average interest rate on our outstanding debt.
Income Taxes
Our provision for income taxes for the three and nine months ended September 30, 2020 and 2019 is based on the estimated annual effective tax rate, in addition to discrete items. Our effective tax rates on pre-tax income were 12.4% and 16.8% for the three months ended September 30, 2020 and 2019, respectively, and 13.5% and 17.9% for the nine months ended September 30, 2020 and 2019, respectively. The decrease in our effective tax rate for the three and nine months ended September 30, 2020 compared to the prior periods was primarily due to higher prior period domestic pre-tax income