Even though it seems there's little likelihood of them being paid, they are still on the inventory, and then added up part of his estate?
He must have been pretty well off to write off 100 pounds in 1633 -- that was a huge amount of money. 
It's not possible from the entry to identify the proportion of the 100 pounds which was without hope.
It may have been only a few shillings.
All this is assuming my interpretation of the relationship between
spearat and
despearate is correct.
I'm still bothered by the use of
a as the conjunction instead of
and/&.
In Latin
a can mean
after, which could make it,
Debts for which there is hope after those without hope (are subtracted). But it's not written in Latin, as far as we can see.
There's plenty of uncertainty here (in my mind).