Token Quotas - Clarification please


Could someone help me understand quotas a little more?

Q1 - Quota limits for user_timeline per 15 minutes are 180 for user tokens, 300 for app tokens. I’m assuming an app could therefore query many users timelines by using the users oAuth tokens associated with each account, so you get 180 requests per user token/account, and then this won’t contribute towards the app token count?

Q2 - when you have a rate of say ‘15 requests per 15 minutes’, then if you perform a request (taking 1 from your quota) and the results are truncated due to paging, then does requesting the next page take another 1 from your quota, or are the additional pages quota-free?

Q3 - regarding direct_messages/sent, in the statement “You can request up to 200 direct messages per call, up to a maximum of 800 outgoing DMs.”,does ‘per call’ mean ‘per page’? So is that 800 DMs across 4 pages? So if they had 1600 DMs, is this considered 2 requests with 4 pages, or 8 requests?