While she blamed the narrow loss on "crucial errors at the wrong time", she made some pointed comments following the match.
"There is certainly a different interpretation [of the rules] and we need to address that because it is impacting on games," she said.
"We need to be looking at it and make it a fair and just competition for everyone, or at least know what is going to be played over here and why."
Hoornweg was confused with some of the contact calls and left ruing a heavy penalty count against her side.
"What is bewildering is sometimes players can be on the ground and there is no [contact] call at all, and other times an arm is lifted and the whistle blows.
"There were two teams going for the ball in most cases and for us to get double the amount of penalties [suggests] that we are obviously doing something very wrong, and we will have to look at that.
"But to see players get knocked to ground and nothing called is a bit strange at times."
As far as wins goes this one was monumental for the Steel.
With the Otago-Southland combined team's play-off hopes hanging in the balance, the franchise could not afford to let the match slip.
Most pundits were picking the Vixens would be too strong for the home side but the Steel produced one its best displays this season to win the game in the dying seconds.
Rookie goal attack Julianna Naoupu calmly slotted the winning goal and picked up the player of the match award for her efforts.
The 18-year-old only got her chance when regular goal attack Megan Dehn was ruled out with an ankle injury on Friday.
TV presenter and former Silver Ferns shooter Tania Dalton joined the Steel as cover but her role was limited to watching from the sidelines as Naoupu drilled 26 of her 32 attempts.
The win has kept the Steel's play-off hopes alive but Broughton said the key was for her side to maintain the same intensity in the remaining four round-robin matches.
"You'd have to say it [the win] was pretty big," Broughton said.
"We took a big step up with our possession count . . . but again we threw things away.
When we're five [goals] up you should put your foot down and we didn't put our foot down."
With the sides trading goals for much of the match the Steel built a five-goal lead midway through the final quarter and looked to have the game under control.
But the Vixens came storming back into contention with a five-goal unanswered burst to level the score 41-41.
In a nervy and clumsy final few minutes it was the Steel which retained more poise.
The Vixens had the better of the early exchanges, opening a 8-4 lead.
Australian defender Julie Prendergast, wing defence Johannah Curran and centre Natasha Chokljat did a good job cutting off the supply of ball to Wipiiti and Naoupu.
World-class goal attack Sharelle McMahon's speed and busy work rate created some problems at the other end.
But Katrina Grant did a superb job chasing around her experienced opponent.
While you can never completely shut a player like McMahon down, Grant's tenacious defence was to be commended.
"I thought Katrina played a very good controlled game of netball and played to the game plan, and it paid off for her.
"She played very well on attack with Erika Burgess.
"They got a lot of ball through for us there."
Melbourne nursed a 24-23 lead at half-time but the Steel outscored its opponent 13-10 to take a two-goal lead into the final stanza.
Wendy Telfer made one of the plays of the game when she caught up with a pass centimetres before it went out of bounds and flicked it back in court before her momentum carried her across the line.
That one moment perhaps best summed up how both sides played the match - with desperation.
The Steel plays the West Coast Fever in Dunedin next Monday night and the Vixens have a tough match against the Waikato Bay of Plenty Magic in Melbourne.
Southern Steel 47 (Julianna Naoupu 26 from 32, Daneka Wipiiti 21/31), Melbourne Vixens 46 (Caitlin Thwaites 28/38, Sharelle McMahon 18/22) Quarter 13-15, half-time 23-24, three-quarters 36-34.
