Mobile phone App - Do they really measuring Voltage and DC Current?

[Kiriakos GR]

I am toying right now with an APP named as Ampere. ( Developer Brain_trapp)

At my Galaxy S5 (G900F), no matter if I turn On,  WiFi, Mobile Data, or close them all.
Ampere App this reads 450mA ....  this does not fluctuates or changes.

https://play.google.com/store/apps/details?id=com.gombosdev.ampere

AI told me that this is software calculation alone.
My phone can measure accurately only voltage at four digits resolution, anything else this is software calculated approximations.

I am unaware to say of which mobile phone models they do support accurate current measurement, due an included current shunt.

In the positive side of things.
Ampere App this succeed reading my replaceable battery as genuine.
Theoretical battery capacity 2800     
Three digits voltage resolution instead of four digits (in hardware chip).
SOC level %
Temperature in Celsius

These are nice to read information's, but they are rather generic. 

In contrast to Galaxy Charging Current *Free* App , this one does not measure actual current either.
Actually this one does not have any discharge monitor, even due software.
What this does is detecting at charging,  the charging speed chosen by the phone, after communication by the charging source.

Genuine Samsung 5.3V charging Block this will force Fast charge 1.7A constant current.
Anything else (charging Block) will limit charge current at 670mA ~ 1A
USB port charging at 500mA
Wireless charging 760mA limit   

In conclusion, prior of you to get in testing a pile of App, you better find first the in hardware capabilities of your phone.