I've gathered some data to figure who did the killing of said shieldball, and you seem to forget a certain Ultimatum piloted by yours truly who killed no less than 4565 metal worth of units during your assault.

List:
11 x Convict = 1680
2 x Felon = 1240
1 x Penetrator = 1000
1 x Racketeer = 350
1 x Scalpel = 220
1 x Bandit = 75

Even worse, I continued to watch the replay in order to see who did the cleaning. I was thrilled to find another Ultimatum, piloted by the same pilot as the last one, killing a whopping 7675 metal worth of units and buildings while dodging a scary stream of fleas.

List:
1 x Funnelweb = 4500
2 x Strider Hub = 1200
5 x Convict = 700
1 x Shield Bot Factory = 600
1 x Spider Factory = 600
1 x Radar = 55
1 x Flea = 20

[Spoiler]