Table:
|  | Year Ended December 31, 2019 |  |
| --- | --- | --- |
|  | Acquisition Costs | Fulfillment Costs |
|  | (Dollars in millions) |  |
| Beginning of period balance | $322 | 187 |
| Costs incurred | 208 | 158 |
| Amortization | (204) | (124) |
| End of period balance | $326 | 221 |
Paragraphs:
Contract Costs
The following table provides changes in our contract acquisition costs and fulfillment costs:
Acquisition costs include commission fees paid to employees as a result of obtaining contracts. Fulfillment costs include third party and internal costs associated with the provision, installation and activation of telecommunications services to customers, including labor and materials consumed for these activities.
Deferred acquisition and fulfillment costs are amortized based on the transfer of services on a straight-line basis over the average customer life of 30 months for consumer customers and 12 to 60 months for business customers and amortized fulfillment costs are included in cost of services and products and amortized acquisition costs are included in selling, general and administrative expenses in our consolidated statements of operations. The amount of these deferred costs that are anticipated to be amortized in the next twelve months are included in other current assets on our consolidated balance sheets. The amount of deferred costs expected to be amortized beyond the next twelve months is included in other non-current assets on our consolidated balance sheets. Deferred acquisition and fulfillment costs are assessed for impairment on an annual basis.
Question:
How are the deferred acquisition and fulfillment costs amortized?
Answer: based on the transfer of services on a straight-line basis over the average customer life of 30 months for consumer customers and 12 to 60 months for business customers