I'd certainly want to inspect things closely to see what is going on with the instrument - a full-up ski ramp on a 335 seems a little unusual. There are options, depending on the player and the guitar:

- If the instrument is wearing something like Dunlop 6105 wire in nice shape (i.e., about 0.095" x 0.047" and leveled to 0.045" or so), and the player does very little work above the body fret (the 19th fret on a standard 22 fret 335 design), one option is to zero out the existing relief and see what would be required on the 19-22 fret section to get everything level; if less than 0.010" at the 22nd, cut in 0.003"-0.004" of relief in 1-18, and cut in the 0.007"-0.009" remaining to remove on the 22nd fret. This would likely run to at 1.6 hours ($165 for this area) with the level/crown/polish and setup work needed.

- Remove what will likely be 8 frets (15 and higher), cut the ramp to level, and refret. Typical charge on a partial is $25 per fret plus setup work ($230)

- Refret at what is usually about $280-$300 in nickel silver and closer to $360 in stainless. If there is significant fret wear otherwise, that might make sense and ultimately be a lower-cost approach that fixing the ramp issue now and having to go in for another partial on 5-14 in a few more years.

On fall-away: conventionally-built acoustics will see flattening of the back and top distortion that will eventually require a neck reset. If the extension is dead level reference the unloaded fret plane, and the top above the upper bout is quite stiff and resists distortion, there is a better than average chance that in 10-15 years, the guitar will have developed a bit of a ramp and require some work if player and action dictate.

We usually cut in 0.010"-0.015" (depending on body size and scale length) on full body and 12 fretters, and 0.007"-010" on cutaways. Up to 0.005" of that fall-away disappears in the first six months of string-up on new guitars, depending on body size, scale, etc. (we build in what is a traditional Martin & Gibson approach, so see the same 'flaws' that those marques see over time).

Ask question some of us do this for a living and have lots of experience to share.

Pat ski ramps are very common in the electric guitar world. I would say that most Fender style bolt-on necks develop them and this is not exclusive to Fender.

I didn't read all the other posts except for a few at the top of the page so my apologies if I don't provide attribution to anything already contributed.

On a 335 style guitar a ski ramp is also not uncommon especially on an Epiphone. Even Les Pauls can develop ski ramps although like a 335 it's a bit unusual. Remember no-one ever brings us anything because everything is honky dory.

Step one is always straightening the neck to as close as you can get to perfectly straight with the rod and then marking with bluing and hitting the fret tops with a long, flattened on a calibrated surface plate leveling beam and reading where you are hitting. This is your road map to fixing this individual instrument, where the ink remains and where it's been removed will tell you where this fret plane needs to be leveled, recrowned, etc.

Be ready to work your butt off milling down that ski ramp, .010 - .015 is too much and it should be flattened out. We have files that we've purchased for straightness and then glued to shop-made handles for the heavy lifting fret grinding. A piece of masking tape on one end of the file and keeping that masking tape over the 12th fret generally speaking while grinding the last frets level is how we do it. Once it's level with the rest of the fret plane using the same technique but this time with short leveling beams and 120 and later 220 we mill in fall away.

How much? When I was building I shot for between .010 and .015" just as Mario does. In the repair world you don't need to go that much. It's an added benefit and crucial for very low action shredder type players on electrics. 335's are often used for jazz too and many jazz players can want and use uber low action and fall away helps with this too.

Lastly fall-away is desirable and in our view part of the value add of taking your instrument to a professional Luthier. It's milled in by many of us as well as some of the top manufacturers such as Collings. Again for uber low action players who do more than cowboy chords and use the entire neck it's essential to their playing style.

Feel free to PM or call me at the shop if you have any questions or need any help I'm happy to walk you though it.