My fill pipe is much longer than yours but had just as big or bigger dip in it. Sloppy construction. I rigged up a small strap to pull it up level rather than undue the hose clamps and trim it. Then, using the filler tube like you, it filled easily.
2018 JayFlight SLX 212QBW
1999 Ford F-250 Super Duty Lariat SC, 7.3L PSD, 3.73
Transfer Flow 50 gal aux; Andersen WDH; Prodigy P2
😁 "If a man says he’ll fix something, he will. There’s no need to remind him every 6 months.