Hi Ellee
When a new plant is bought and brought home it should be put in the area you're going to have it permanently for at least a week so it gets used to it's enviornment. Up on repotting , no plant should have fertilizer right away until it starts to show new growth. Yep yellowing of leaves is too much water that's true,, but so is shock, including leaf drop.
I would let it dry out some more,, I've never trusted those water meter,, because they are for primarily good for moisture loving plants( Plants .that the soil needs to always feel like a wrung out sponge.)
I use the sta- green brand as well but only for outside plant in ground, even tho it says it's for houseplants as well.
For house plants I only get house plant soil _ Plain potting soil and I mix a little of my compost with it for organic nutrient, It seems to work fine,
Right now the water meter is on the very low end of moist, almost dry but I'm hesitant to water as my first thought was: Yellow leaves = two much water.
Trust your instincts,,
:wink: