Wales's U18 counterparts Scotland won the superb match at Hughenden; the result means that both Wales and Scotland finish with two wins from three matches but the Welsh side will be disappointed that they could not complete the hat-trick.
Against Scotland, Wales suffered from a surfeit of sin-binnings - three in total from French referee Eric Gauzons.
"We were definitely affected by what I thought were harsh yellow cards," said Wales Coach Simon King. "Scotland scored both their tries when we had players in the sin-bin" he added.
"Yet Scotland fully deserved their win. We possibly peaked against England on Wednesday and we started with several new players against Scotland" stated King.
"Overall this has been a good tournament. The standards over all the countries have risen. The pleasing thing for us is that ten of our squad will be available for next year" said the Wales Coach.
Wales looked to be on course for victory when they converted a line-out steal into points with a try by winger Adam Hughes made by fullback Jason Tovey's break, and the conversion from outside half Joe Deacon.
Then, after Wales loose head Tom Price had been sent to the sin-bin for a repeated scrummaging offence, Andy White opened Scotland's points account with a penalty goal from 30 metres.
A second yellow card, this time to temporary replacement Aaron Coundley, left Wales down to thirteen men. Scotland inevitably attained a score as fullback Steve Aitken cut through midfield to score under the posts leaving White with an easy conversion.
A second half try by lock Nicky Campbell, converted by White, extended Scotland's lead but Wales recovered with a penalty goal by replacement outside half Dan Biggar and then gained an advantage when Scotland centre Rob Johnston was sent to the sin-bin for preventing fair release.
In Johnston's absence Wales attacked through their backs but good Scottish defence kept the Welsh speedsters in check. Wales again threatened but great cover work by Dymock saved the situation and in the process procured Scotland a penalty. White again kicked to the corner to set up an attacking position.
There was no immediate gain but replacement prop Rhys Williams was dispatched to the touchline by the referee and the points punishment came from the ensuing penalty kick from White that gave the Scots a 20-10 lead.
A massive penalty goal from Biggar brought Wales back into contention. Scotland, despite struggling in the set piece, came roaring back and seemed to have scored when Richard Gray plunged over but the referee had noted a Welsh transgression.
This time White was just wide with his kick but it mattered little. When Wales were again penalised White had merely to kick the ball into touch to ensure a Scottish victory.
Scotland U18: Tries: Aitken, Campbell. Cons: White (2). Pens: White (2)
Wales U18: Try: Hughes. Cons: Deacon. Pens: Biggar (2)
S Aitken (Ellon)
F Thomson (Gala)
P Louden (Captain, Edinburgh Academicals)
R Johnston (Newark)
C Findlater (Highland)
A White (Annan)
C Jackson (Newbury)
C Godfrey (Merchiston)
F Gillies (Haddington)
D Morton (Bristol)
R Gray (Glasgow Hawks)
N Campbell (Allan Glen's)
S Dewar (Strathallan)
C Fusaro (Howe of Fife)
T Drennan (BATS/Trinity Academy)
A McKenzie (Barnard Castle School)
A Dymock (Dundee HS)
F Brown (Biggar/Merchiston Castle School)
D Orr (North Berwick HS)
G Cameron (Hawick Wanderers)
J Taylor (Merchiston)
J Tovey (Cwmcarn/Newport)
A Hughes (Croesyceiliog)
J Harries (Bro Myrddin/Carmarthen Quins)
A Beck (Neath/Tonmawr)
R Bayliss (Brecon/Pelenna)
J Deacon (Rumney)
R Downes (Rhydyfelin RFC)
T Price (Builth/Builth Wells)
R Guest (Captain, Coleg Sir Gal/Llanelli)
S Maguire (St Joseph's/Chepstow)
A Sweet (Pontypool/Pontypool United)
D Partridge (Llantwit Major)
L Mills (St David's/Rumney)
J Thomas (Pencoed/Ynysybwl)
R Pitman (Ospreys Academy)
A Coundley (Cross Keys/Blackwood)
R Williams (Blues Academy)
L Bray (Cross Keys/Blackwood)
J Tipuric (Swansea/Trebanos)
L Williams (Cowbridge/Llandaff)
D Biggar (Gowerton)
J Loxton (St David's/Llandaff)
T Rees (Coleg Sir Gal/Llandybie)
Referee: E Gauzans (France)