Oil Level Gauge Variations
 

Last night I was driving home and I noticed that the oil level guage on my Box had only two bars left. This seemed odd because I only bought the car four months ago and they told me that they changed the oil then. Just to be sure, I went out the next morning and just turned the key in the ignition and now it says that I have all but two bars left. Which is right and should I be worried that the guage is showing such a range of results? Also, if I decide to change the oil, the previous owner used Castrol 5W30 and I plan to switch to Mobil 1 0W40 will this be ok? Thanks!

I had an oil change this week and I was down one bar. That digital thing should only display a reading when the car is cold. Hot readings just causes confusion.