The path to the quarter finals for Rob Penney is well documented while Costello needs his side to take two points from their meeting with Plymouth Albion on Friday night (Temple Hill) to progress to the play offs as Costello sees it. " Rotherham beat Plymouth 21-3 so that means basically it's down to ourselves and Rotherham.
"We need two points to ensure we go through top but as far as that's concerned we have to win, that's our attitude. We play Friday night they play Saturday so because it's in our own hands it's very very important we get the result we need Friday. We dont want to be waiting till Saturday to see what happens in Rotherham.
"Rotherham are at home (v Aberavon) and we're planning that they'll get five points. So we've just gotta go out beat Plymouth Friday night."
And in the event of the planned win Munster will have to take to the road in April. "Even if we get a win on Friday, that would give us five wins and a draw. That still wouldn't be enough. Four teams have shot out in front so for us now it's just a case of making sure we qualify and take things from there then."
For Penney, the water is a little murkier.
Four sides have qualified for the Heineken Cup quarter finals but ten more can mathematically qualify along with Ulster, Toulon, ASM Clermont Auvergne and Harlequins.
But in realistic terms Montpelier, Leinster and Munster are vying for the two 'best runner-up' spots with Saracens and Leicester Tigers or Toulouse set to make up the seeded group.