Why is Verizon charging for 30% more data than my iPhone reports? (see proof)

[wallus]

Verizon shows 1 GB more usage for a period beginning on April 2, 2016, than my cell phone, for a period beginning on March 30, 2016.

What could possibly account for such a difference?  Verizon may be charging me for 1 GB more data in a 2 day shorter time period.

See below (1) a screen shot of My Verizon taken earlier today for the data usage of my phone specifically, (2) a screen shot taken at almost the same moment from Settings -> cellular, (3) a screen shot after scrolling down to show the last time that iPhone cellular usage statistics were reset, which was two days before the billing cycle began for Verizon. Verizon Wireless Customer Support @verizon

[wallus]

Update: my billing cycle started on March 28, I must have used a whole gigabyte on March 29.  I retract this post.  My apologies.

[sick-of-it-all]

It depends on what metering they use. 95th percentile is the standard.  I've never got a solid answer. Remember, dropping an image in a text makes that text an MMS and therefore data. So not unlimited free as one would think. We also don't know what Apple meters and how either.