The most recommended efficiency configurations on this forum for a 2 cuft softener are 3k grains/lb (16 lbs to regen 48K grains capacity) or 3,333 gr/lb (12 lbs for 40K gr cap) as these are a good balance between salt efficiency, water quality and regeneration frequency.
I'm not understanding why the 10-day override is set. A short override is often required when the softener is to remove iron, but then, a higher salt dose is also needed to reduce iron fouling. With iron exposure, salt efficiency will not be the main concern.
In programming a short override, if there is unused capacity remaining when the override setting lapses, the resulting regeneration cycle will regenerate capacity that does not need to be regenerated. The unused capacity is wasted which then results in lower overall efficiency, even if the salt setting chosen is extremely efficient. With a meter initiated softener, the most efficient operation will be for the flow meter to fully manage when regeneration occurs, based on the usable capacity programmed (P7) being consumed.
Suggest programming 12 lbs/40K which at 140 gals/day @ 25 gpg is anticipated to result in approx 11 days between regen cycles. A 15 - 18 day override setting will allow some leeway for periods with lower than average water consumption.