PING cartridge, is it really 200units?

[yanki01]

Since being on my pump for a month, my sugar levels have never been better. i love this pump!!! When i prime/rewind and load the cartridge with a full dose of 200units of insulin, it never stops at 200units, usually stops around 190-194units? why is that, does anyone else's pump do this? after looking at the whole picture, i believe I waste a good 15-20units going through a full switch of inset & cartridge. just wanted some thoughts on this, thanks!

[Joeprep4820]

For me a god 12-15 units go through the tube, plus 1 unit in the cannula, so it makes sense to me. I also believe the number on your pump screen is lower than the amount in the reservoir. On mine I let it go to 0 on purpose, then measured a good 10 units left in the reservoir, so that might be it as well.