Still way to early to book for Oct.
Not always - we booked our Dec car rental when it first became available to do so and now even the price I have is no longer avaialble, everthing is 25-50% more. For our August reservation the price we have is now also higher then when we first booked about 10 monhts in advance.
We will keep checking but if the prices do not come down we are happy with what we have as I cannot even find those prices any more. The way I have always found car rental rates is that the more cars they have the better the price. The less inventory they have the prices increase. That is not to say if they have more cars than they think closer to the price will not come down but I rather have a lower price to begin and then keep checking in case anyhing else becomes availale which it doesn't always