This is actually something I’ve run into lately myself. I found this quote sourced from d20pfsrd Magic Armor
… Magic Armor bonuses are enhancement bonuses, never rise above +5, and stack with regular armor bonuses (and with shield and magic shield enhancement bonuses). …
In addition to an enhancement bonus, armor may have special abilities. Special abilities usually count as additional bonuses for determining the market value of an item, but do not improve AC. A suit of armor cannot have an effective bonus (enhancement plus special ability bonus equivalents, including those from character abilities and spells) higher than +10. A suit of armor with a special ability must also have at least a +1 enhancement bonus.
This effectively means that the enchantment bonus of the item is limited to +5 but you can go up to +10 in cost by adding abilities such as Billowing or Spell Resistance that don’t effect the enchantment bonus. That’s why the cost table goes up to +10.
I know that the Cloak of Resistance from the question isn’t “armor” in the sense that it goes in the armor slot and adds AC, but I found very similarly worded entry on d20pfsrd Magic Weapons so it’s probably safe to assume this applies to all magic items.
… Magic weapons have enhancement bonuses ranging from +1 to +5…
… Some magic weapons have special abilities. Special abilities count as additional bonuses for determining the market value of the item, but do not modify attack or damage bonuses (except where specifically noted). A single weapon cannot have a modified bonus (enhancement bonus plus special ability bonus equivalents, including those from character abilities and spells) higher than +10. A weapon with a special ability must also have at least a +1 enhancement bonus.
So in the end, you can have your Cloak of Resistance +5 with Spell Resistance, but not a Cloak of Resistance +6.