62session and is then charged to you based on the terms of your Services.Depending on your Services, usage may be charged against anallowance or on a fixed price per kilobyte. Usage charges may berounded up to the next cent at monthly or other intervals. In certaininstances, you may not know that your session has not ended. As longas your device is connected to our network, you will incur data usagecharges. You will be charged for all data directed to the internetaddress (or "IP address") assigned to your device, regardless of whoinitiates the activity or whether your device actually receives the data.This includes, but is not limited to, the amount of data associated withthe particular information/item (e.g. game, ringer, email, etc.),additional data used in accessing, transporting and routing thisinformation/item on our network, data from partial or interrupteddownloads, re-sent data, and data associated with unsuccessfulattempts to reach websites or use applications. Based on these and anumber of other factors (e.g., the specific application, networkperformance, etc.) data used and charged to you will vary widely, evenfor the same activity. Estimates of data usage – for example, the size ofdownloadable files – will not be accurate or a reliable predictor ofactual usage. Your invoice will not separately identify the number ofkilobytes attributable to your use of specific sites, sessions or services.Taxes and Surcharges. We invoice you for taxes, fees and othercharges levied by or remitted directly to federal, state, local or foreigngovernments including, without limitation, sales, gross receipts,Universal Service, use, and excise taxes. If you claim any taxexemption, you must provide us with a valid tax-exempt document.Tax exemptions are not applied retroactively. We also invoice you forsurcharges that we collect and keep to pay for the costs of complyingwith government programs such as number pooling and portability,and Enhanced 911 service; these charges are not the taxes norgovernment imposed assessments.Invoicing & Payment. Invoicing cycles and dates may change fromtime to time. Monthly recurring and related charges for Services aregenerally invoiced one invoicing cycle in advance. Other charges areinvoiced soon after they are incurred. Most usage is generally appliedto the invoicing cycle in which they are incurred, but in someinstances may be applied to subsequent invoicing cycles. You are