According to the SRD:
https://www.d20srd.org/srd/magicItems/potionsAndOils.htm
It lists a Potion of Protection from Arrows with 15/magic is this a mistake? According to the spell this should not be possible as the damage reduction is only 10/magic.
https://www.d20srd.org/srd/spells/protectionFromArrows.htm
If this is not a mistake, should the part which reads:
'Once the spell has prevented a total of 10 points of damage per caster level (maximum 100 points), it is discharged.'
instead be adjusted by understood implication to read
'Once the spell has prevented a total of 15 points of damage per caster level (maximum 150 points), it is discharged.'
when applied to this particular potion? I have read the 3.5 DMG errata and nothing is mentioned in regards to this.
Best Answer
It may be more powerful...
The regular protection from arrows potion costs 300, the more powerful one costs 1500 gp, and is 50% more effective. By the creation rules, to get that price, the caster level would have to be 10th, and the spell level 3rd, or perhaps caster level 15, but that doesn't give anything other than duration. In Dungeons & Dragons 3.5 revision rules...
... because it fell through the cracks
It appears it's a holdover from the 3.5 update, likely from a version of protection from arrows that became more protective with caster level, as the 3rd edition version required higher magical bonuses depending on caster level, eventually getting to requiring +5 arrows to bypass the DR (Player's Handbook 2000, 240, emphasis mine).
I suspect that the authors and editors had an interim playtest version of the spell where instead of the magic bonus increasing, the DR itself did, since they had changed the way that DR worked, but eventually settled on the version in the 2003 Player's Handbook, 3.5 edition revision.
It's a mistake, but not a typo.