But it was not goalkicking which decided the fates as West Coast Tim Priest was likewise wayward in both halves, but instead Wanganui's much-maligned backline was yet again without direction on a day where two very strong forward packs fought to a stalemate.
Too often winger Sailosi Naqiso got isolated and took the wrong option, while there was no excuses for back-three partners Robert Hughes and Jason Temara after letting dangerous West Coast winger Maleli Mudu slip past them with an inch of space down the sideline for a stunning solo try in the 26th minute.
No8 Rowan O'Gorman was left alone out wide which Priest spied with a clever cross kick to waltz in for the first of his two tries, meaning Wanganui turned to face the wind with a three-point deficit as opposed to a mandatory 10-15 point lead.
Prop Vaan Rahina being sinbinned for knocking a pass down in the first half didn't help either, but West Coast also lost their hero in O'Gorman with a yellow card after 65 minutes with Wanganui hot on attack.
It was only when veteran Ace Malo was moved from centre back to his preferred fullback that Wanganui showed any kind of punch through the midfield.
The finger of blame can go no further Wanganui's veteran forwards secured several turnovers during a first half which was otherwise one-way traffic, while Nick Cranston took personal responsibility for the lineout and had probably his best game all season.
But unlike years gone, West Coast had the firepower to counteract them as aggressive lock Josh Manning and inspired birthday boy flanker Alan Monk were outstanding for the visitors.
Leaning on the guard rail in front of the dressing room, contemplating an unpleasant future, Hoskin had to be frank.
"We played really terrible. Switch on, switch off."
The backline could not put it together for long enough periods and had "blown their lightbulb", something Wanganui has spent an entire campaign trying to correct with little success.
"We were fine for 15 minutes and bloody terrible the rest of the time."
It will be a big ask to lift the team for a home Lochore Cup semifinal in a rematch against Buller this Saturday, another Coastal team to scalp Wanganui this year.
The situation again spotlights the admirable but debatable philosophy of not bringing in more import players to shore up gaps in quality, given the necessity of using career fullback Malo in the midfield while choosing teenager Hekenui to run the cutter for the first time ever on such a massive occasion.
But when asked if Wanganui was just missing one or two key pinch hitters, captain Peter Rowe politely declined comment.
For him, the issue remained the inability of those on the pitch to put together a consistent, whistle-to-whistle effort.
"In a patch there we decided to play some footy. But you've got to do that for 80 minutes, not 30 minutes."
While "initially disappointed" to be heading into his first Lochore playoffs, Rowe said the team must keep it together for another fortnight to salvage their year.
"A lot of people put a lot in [to our season]. I don't want to throw that all away."
Against the run of play, Wanganui opened the scoring as No8 Lasa Ulukuta spread wide to reserve hooker Roman Tutauha, fresh on for a blood bin, who fed Naqiso and in turn got it back from him to dive over.
A signature Wanganui drive to the line was thwarted by Manning and West Coast swept back upfield, with Mudu cutting free and slicing through two weak tackles, despite no room to move, to score in the corner.
While O'Gorman was maybe a step offside, there was no doubting the vision of Priest to make a pinpoint cross kick despite the breeze for the Coasters to hit the lead late in the half.
Needing a good start to the second 40 minutes, Wanganui fell apart as the ball was lost immediately and after a series of phases, Monk forced his way through and set up second-five Andrew Connors right beside the posts.
Minutes later, West Coast surged again and O'Gorman had his second try after the ball travelled through several sets of hands. Wanganui made changes with Malo dropping back and Soonalote Tauailoto coming on and once again it was like they just woke up Temara and Malo combining after Priest missed touch to get on the front foot, then Evans taking off to score after a Tauailoto bust.
Malo chipped and re-gathered to set Wanganui off again, leading to Jason Hughes smashing over for another try within seven minutes.
But two minutes later a lost ball led to West Coast earning a penalty for Priest in good position despite the wind. The score was now 25-19 entering the final quarter.
Another brilliant Malo run brought Wanganui back on attack, leading to O'Gorman's yellow card and Jason Hughes dashing over without a hand on him.
But despite momentum and a lions' share of the penalties in the final 12 minutes, they were destined to get no closer as West Coast's desperate tackling held firm, the breeze making three-pointers a non-option.
West Coast 25 (Rowan O'Gorman 2, Maleli Mudu, Andrew Connors tries; Tim Priest con, pen) beat Wanganui 24 (Jason Hughes 2, Andrew Evans, Roman Tutauha tries; Zyon Hekenui 2 con).
Halftime: West Coast 10-7