This is not dependent on the version of ASE, its basically the way ASE log based recovery works.
Let me explain u a bit more.
In ASE database consist of three default segments
For more information on segments please follow below link
what is segment in sybase?Know System segments system,log segment,default segments.
Now for your situation, the option you mentioned are fine to deal with.
Its totally depends, the option you use, on the how much the recovery of the database is important, in case of disaster.
1. If you use trunc log on chekpoint, option, all the committed transaction from the log will be removed from database logsegment (syslogs table), everytime ASE checkpoint runs.(which is default on every 60 sec)
2. If the database recovery is important up to time, in case of disaster , you must not use the trunc log on chkpt, and should go for dump tran.
the method of SP u told in you post is good, which seems to be a complex SP for checking the logsegment and deciding when to run dump tran. (You must be talking about the last chance threshold SP
Whereas there is lot more simpler method and is used every where( I assume), which is schedule a job to run the transaction dump using a scheduler (cron in case of UNIX plateform) every 10 or 15 mins, and use your last chance threshold SP also, to take transaction dump if transaction log is crossing the threshold defined by you.
I hope my post will be helpful to you