(Bloomberg) -- Apple Inc.’s attempts to justify the 27% fee it charges developers for purchases outside its App Store backfired as a skeptical federal judge questioned an executive about a company-commissioned study showing half that rate would be reasonable.Most Read from BloombergChina Attempts to End Property Crisis With Broad Rescue PackageA 25-Year-Old BofA Trader Dies Suddenly at Industry OutingWith a BlackRock CEO, $9 Trillion Vanguard Braces for TurbulenceVoters Prefer Trump Over Biden o