HIRAM WEST'S MILL IN 1870

As I mentioned at the conclusion of my post about Hiram West's farm on the 1870 Census Agricultural Schedule, even though Hiram had a smaller farm than his brother Jonathan Phelps West, his farm's value was only $50 less and he could afford to have a hired hand. The reason he could was that he had another source of income, two mills.

I found an entry for a "Haraig Y. West" on the 1870 Federal Census Products of Industry Schedule at Ancestry.com. That should give you an idea of how hard to read the handwriting is on the document. But I knew it was Hiram as soon as I saw the name "Asa" as his one employee. That had to have been Hiram's brother Asa West. Here's my transcription:

Name of Corporation, Company, or Individual producing to value of $500 annually:
West, Hiram F.
-Asa

Name of Business, Manufacture, or Product: Starch Mill
Capital(real or personal) invested in the business: 2000 (dollars)
Motive Power:
Kind of Power (steam, water, wind, horse or hand): water
If steam or water, no. of horsepower: no entry
Machines:
Name or Description: Grist Mill
Number: 1
Average Number of Hands Employed:
Males above 16 years:
Females above 15 years:
Children and Youth:
Total amount paid in wages during year:
Number of months in active operation, reducing part time to full time: 7
Materials (including Mill Supplies and Fuel)
Kinds:Potatoes
Quantities:8000 bushels
Value(omitting fractions of a dollar):2000 (dollars)
Production:
Kinds: illegible
Quantities:28 tons
Value(omitting fractions of a dollar): 2520 (dollars)

There follows a note scrawled across the page beneath the entry. I can't
make out the first two words in the two sentences and they seem
disjointed:

"(?) (?) described grist mill grins for owners & receives toll
(?) (?) described starch mill (?) potatoes and make (?) at their own 
risk"

What am I to make of this? Apparently Hiram was paid by those whose
grain he ground at the grist mill by a portion of the end product, but he
allowed those with potatoes to use the mill themselves at their own risk?
Was the profit he made only $520? And Asa must have been a partner,
not an employee. Trying to interpret this one is frustrating!

At any rate, it must have been a profitable operation because, as we'll
see, Hiram's business ventures had expanded by 1880.