I think this assumption also depends on the character.
It seems most applicable to classes with only 2 key stats. Take for instance a half-orc brutal scoundrel rogue. A typical player would likely start off with 16s in both str and dex (so that he starts with 18 str/dex), 12-13 in con and leave the rest at base. He will then probably apply the +1 stat bonus every 4 lvs to str and dex, the stats which have the most impact on the effectiveness of his character.
While +1con would grant an extra surge, he might be tempted to just leave it to lv11, when he gets +1 to all stats.
So there are definitely exceptions.