Pollock, who had no previous convictions and a clean driving record, successfully appealed the period of driving disqualification imposed.
The three years' disqualification was quashed and a period of 18 months' imposed in lieu.
In her judgment Justice Lowell Goddard said sentencing Judge Jonathan Down had referred to a police crash report, which concluded "both [Pollock] and [Uetaha] had contributed in varying degrees to the cause of the accident".
"The children were not supervised by an adult and had continued to chase the mower despite being told to go away by [Pollock]," the report said.
During a prior sentencing indication Judge Down had accepted Pollock had also not acted in a "bullish or bloody-minded way".
The 13-year veteran driver was operating the tractor for about 11 minutes before three children, aged 10, 8 and 4 had begun chasing the mower.
During sentencing Judge Down said Pollock "stopped, turned around to them, called out to them to stop, tooted your horn, waved and tried to shout them off, but despite your best efforts they continued to chase the mower".
Witnesses told police they saw Uetaha about 35m-40m from the tractor when he began running and "side-stepped" towards the machine before trying to step back, but it was too late.
Justice Goddard said: "As [Crown prosecutor Clayton Walker] submitted, this tragic case is, fortunately, unique.
"Accordingly, although there are many cases dealing with dangerous driving causing death, there are none which have dealt with this particular type of factual scenario.
"As Mr Walker also responsibly conceded, while [Pollock's] offending involved a serious lapse of judgment, it did not involve the usual circumstance of dangerously driving in a car on a road. Further, [Pollock] is an elderly man with an otherwise good record."
The 73-year-old has suffered from major depression and post traumatic stress disorder following the incident while also reliving much of his own 3-year-old son's death, which occurred in similar circumstances.
The council worker wrote a letter of regret which was read by his lawyer, Andru Isac, during sentencing.
"Words cannot say how sorry I am for this terrible accident that we will have to live with for the rest of our lives."
Pollock wrote his heart was "full of sadness" and he could understand the pain the family was going through after also losing his son at a young age.
"I can only ask that one day you can look into your hearts to forgive me."
He continued to be employed by the council throughout the court case, while performing other duties, but retired on June 6.
Last month the Hastings District Council pleaded not guilty to charges over Uetaha's death, laid by the workplace safety agency, WorkSafe New Zealand.
The charge relates to the Health and Safety in Employment Act 1992, under which employers need to ensure that no action or inaction of any employee while at work harms any other person. The council will appear in court on the matter again next month.