It really comes down to how many bidders look at the lens.
In the last couple of months, there were several Pentax-A 70-210 f4 going for around £80 and all sold.
Although I wanted one for the continous aperature, I held out and got one for £31 delivered. Not only that, but it is totally mint, in the box with all the original documention, warranty card etc.
I think this was mainly due to the finish time, which was when most people are out.
You may get a pleasant surprise when you sell, just time it right and hope more than one person wants it.