Yeah, Fe especially will not last overly long.
I would try and maintain the regular EI levels throughout the week.
Even if nothing in there appears to be using the nitrates, I would still try and maintain around 10ppm. I wouldn't reduce nitrate dosing based on the little nitrate usage, but that's just me.
Just to be clear, I don't mean dose 10ppm every day, every other day, once a week or whatever, just try and maintain that level.
In my tanks, (extreme) nitrate deficiency shows as increased root growth (especially above the substrate).
Alas, in the great scheme of things, I have little knowledge in growing aquarium plants considering my short experience span, so take it with a grain of salt.