Data providers supply different data and this doesn't make much difference in a time chart but tick charts can be very different. That is because some send all the tick data and some send sampled data. Having sampled data can be a good thing if your software can't cope with the torrent of data at a news release. So someone looking at a tick chart from IB's data will have a different tick setting from someone using eSignals' data. If you knew the conversion factor between the data providers the charts would look much the same.
The tick data coming straight from the CME has changed. They bundle it, and there's no software that unbundles it, so you may think you're trading off the same 144 that your grandma did, but you're not.
I missed the question a few pages back, but yes, data comes from the exchanges and your software produces the time charts. The thing is that the CME began bundling its ticks, so the data that it sends is now different. Your software will still produce 144 ticks, but they won't be what they used to be. This will affect future, not sure about stocks. Other things such as premium numbers, or trin are all computed by your software, these do not come from the exchange.
Just remember when 144 was invented it was anticipated that these changes would take place. This is the true time for 144 to show its mastery of the markets. It's like the Mayan Calendar and 2012 is, well, you know about that...