These TCG rulings were issued by Upper Deck Entertainment and have since been deemed unofficial by Konami. They were previously considered official and can still be correct, as long as they follow the official gameplay rules, or unless Konami has issued a ruling that says otherwise. References: 
Pole Position: I have "Pole Position", "Luminous Spark" (+500 to LIGHT), and "Gemini Elf" (1900 ATK / EARTH) face-up on the field. "Gemini Elf" is the monster on the field with the highest ATK, so it is unaffected by Spell Cards. If the opponent Summons "X-Head Cannon" (1800 ATK / LIGHT), "Luminous Spark" will raise the ATK of "X-Head Cannon" to 2300, making it the highest ATK monster on the field, so it's unaffected by Spell Cards, so it drops to 1800 ATK, then increases to 2300, then drops to 1800, etc. This would create an infinite loop. Therefore, the opponent cannot Summon "X-Head Cannon".
Susa Soldier: When this card inflicts Battle Damage to the opponent it is halved, regardless if it was a direct attack, or from an attack against another monster. For example, if your "Susa Soldier" (ATK 2000) attacks the opponent's "Gemini Elf" (ATK 1900), the opponent will take 50 points of Battle Damage. The damage points are rounded up when there is a fraction.