Acclimitization is always important. You can either spend more time at Puenta del Inca or get on the trail and just take longer to get to base camp. The extra day gives you time to visit the south face as well which is a good thing. Another night near grass is nice too compaired to what lies ahead for the next 2 weeks. Its not necessary but it usually helps the red blood cells.
"So I was sitting in my cubicle today, and I realized, ever since I started working, every single day of my life has been worse than the day before it. So that means that every single day that you see me, that's on the worst day of my life."
--Peter Gibbons (Office Space)