I considered that but after searching the net for many tubes of 2 x 305
mm, including the site you indicate, and I didn't find one that
consumes more than 7 mA, on the stated characteristics I mean.

So I assumed that there are no tubes consuming 13 mA and mine is
probably manufacture defective or faulty in some way; am I wrong?
I think the inverter is ok because the current is normal with the old
tube.

One other thing I didn't refer is that I can feel the tube warmer than
I would expect, more to the hot side, from the outside of the LCD.



Well I haven't encountered differences like that myself yet, but it's
possible the tube for whatever reason was designed for a lower voltage,
which will often cause the current delivered by the inverter to be higher.