So I just bought a horse with broken wings attached to check how bad the false advertisement was (magnitude displayed everywhere is 3k with 100% bolster and it's definitely not a Tunnel Vision), and it was worse than I thought. You'll find the numbers for deflected / regular (unmitigated) damage :

on my Arbiter loadout :

Noble Pegasus :

• 85526 / 162500 (243750) regular hit (as if magnitude = 1537)
• 100507 / 190964 (286445) crit (as if crit sev = 17.5% while it's 66.3%, or magnitude = 1086)

Lance of Faith (110 mag) :

• 8312 / 11630 (17445) regular hit
• 13821 / 19340 (29010) crit

Lance of Faith after Pegasus :

• 12932 (19398) regular hit -> 11.2% damage (it's inline with the 15% bonus as damage bonuses are additive... most of the time... but it's written 38% on the combat power when you equip it...)

Tunnel Vision (3k magnitude) :

• 279317 (418976) regular hit
• 464469 (696704) crit

on my Devout loadout :

Noble Pegasus :

• 63299 / 120269 (180403) regular hit (as if magnitude = 1789)
• 71327 / 135521 (203281) crit (as if crit severity = 12.7% while it's 61.3%... or as if magnitude = 1250)

Sacred Flame (90 mag) :

• 4214 / 6050 (9075) regular hit
• 6863 / 9854 (14634) crit

So, yes, it's broken. Don't get fooled by the false advertisement. And the whole damage calculation is broken anyway... Something I've already experienced with the Cleric Daily Powers and many other things... The lack of quality control is the reason why I'll uninstall this game very soon...

PS : if anyone is interested, the AD to Zen exchange takes about 71 days on PS4 currently.