Cox won the race named in his family's honour - The Cox Family Celebration Trot - when the 6yr-old ran to an emphatic five-length victory in Hoffman's colours.
She produced 99 winners in partnership with Graeme Anderson and 52 in partnership with Cox.
The Waikouaiti trainer said she was delighted to notch her 200th career victory.
"I was pretty stoked to get it. It was a big thrill."
The always humble Hoffman was quick to credit others for helping her reach the milestone victory.
They included her former training partners and her staff.
"I have had a lot help along the way. Graeme kicked it all off, getting me involved in harness racing," she said.
"Jonny and I had a great run training winners when he was down here.
"I have got great staff at them moment with Madeline Seuseu Musgrave and Nigel Chalmers.
"And Aaron Johnson is fantastic. We are luck to have him as our float driver.
Hoffman was just also quick to deflect praise on to her owners.
"I have had a lot of loyal owners help me get the 200 wins.
"Gerald Cayford has been especially good to me; he has been a great help."
Hoffman has trained the bulk of her 49 winners as a solo trainer from Cayford's Waikouaiti property.
And many of those have been problem horses other trainers have not been able to get success with.
The horsewoman said the move from her former base at Westwood Beach has had been brilliant for her.
"I love it up here; it has been a great move."
The Cox Family Celebration Trot was formerly known as the Harry Cox Memorial Trot.
This year the change was made as the Cox family have plenty of recent personal milestones to celebrate.
One of those came when
Cox got engaged to Kimberly Butt last month.
Another came when Cox's father, John, celebrated 46 years of service with the New Zealand Fire Service, recently.
The jubilation Cox felt when winning his family's race was evident when he gave a big salute with his whip as Imran Khan approached the winning post.
"It was a huge thrill to win that race. It was pretty special, all right," he said.
Cox said helping Hoffman to her milestone win made the victory even more special.
"Amber does a great job. She deserves all the success she gets."
Imran Khan provided Cox with his third win in the newly renamed Cox Family Celebration Trot.
