Audio Additives vs Acoustic Sounds Digital Scale

I have an Acoustic Sounds metal digital scale. It looks identical to the Audio Additives one. On my Acoustic Sounds scale, the cart magnet makes the platform and scale read negative numbers prior to lowering the cart onto the scale. I use the tare button to 'zero' the platform prior to lowering the cart.

The Audio Additives scale on the Music Direct website says the metal case is non-magnetic. Does this include the scale too, unlike the Acoustic Sounds scale?

Anyone who uses the Audio Additives scale, could you please let me know if its magnetic or not? In other words, does the scale require taring due to suspending the cart over the scale making it move from zero?

As a side, I have heard some say the taring in a magnetic situation is not needed and when you lower the cart onto the platform, it weighs the actual weight/force of the cart. This doesn't make sense to me as before the stylus touches the scale platform it should read zero in my mind and not, for example -0.051g.

Thanks in advance for any info.