Defragmentation on SSD drives

We just moved our Sybase ASE15.7 databases from standard "mechanical" HDD drives to SSD drives (IBM SAN).

We suspect that with SSD drives, ASE indexes/tables will require less maintenance against fragmentation.

1) Is reorg/recreate maintenance on tables/indexes still relevant with data on SSD drives?

After moving the db devices to SSD drives, I still see index fragmentation using derived_stat() on sysobjets/sysindexes values.

So I suspect that reorg/recreate indexes are still important but their impact on SSD won't be as important as on standard HDD.

2) Is the concept of fragmentation applicable when a table/index is sent to cache?

In other terms, once the object is loaded in cache, should we ignore the fact that the table was initially fragmented?

Thanks,

Vincent