No! The main point of this TM-Panasonic contract is to make sure Panasonic will be capable to increase production probably by late 2014 - starting year 2015 to certain higher levels compared to an old contract. It would not have an immediate effect in the coming months. Or next few quarters. Problem is a
lead time. It definitely more then half a year. And probably more then a year.
In fact even before new agreement was signed one of Panasonic's supplier announced plans to triple production, and it takes them 9 months to do it (more if you include planning phase,
Sumitomo Metal Mining to almost triple lithium nickel oxide production to meet planned demand for Panasonic cells for Tesla EVs ). But it is just one. Panasonic itself had to expand and the rest of supply chain had to do it too.
To put it into perspective, old contract was asking Panasonic to increase production to supply enouph cells to produce up to 35k battery packs in 2015. Quite a slow increase, Panasonic already producing enouph cells for 25k+ battery packs yearly. New contract seems to ask Panasonic to increase production rate for up to 90k battery packs in a year 2016 (hard to estimate but roughly in the ballpark of that number).
So this is one important part of the agreement. Another one is a price of cells. And it is impossible to know when new prices would come into effect. Contract details are private. And price Tesla paying for cells is dependent on volume. New contract might even superseded old one immediately after signing. But even if that was the case(not granted), Tesla would still move to lower prices gradually, as TM consume more and more volume.