x5 is max multiplier offline in CM.
Tyres wear quickly to 80% (tyre wear scale 13 in Sidekick) but then the deg. rate slows down.
Rears went quickly, giving a big imbalance, but around lap 4 the rears plateaued while the fronts kept at the higher rate, slowly bring the balance back.
Therefore, as the race wears on and balance comes back it would be better to stay out than pit for new tyres.
I say, max out fuel and tyre multiplier, and even if it doesn't force a pitstop, it will add variability.