for roughly about RM 33K only for the designer's fee (interior and exterior) should be okay if and only if they could provide you a very detail scope of works. Rate persqft is average rate market. This not including building plan submission correct? if include with local authority submission should be okay.. if without, they must come up with full scope of detail drawings not just space planning.
example
1) toilet detail with tiling setting out plan
2) built in furniture detail -working drawings
3) schedule of finishes / ironmongeries / bathroom accessories
4) Reflection ceiling plan (RCP) with setting out lighting points and leveling point
5) Site management / monitoring
6) BQ for the ID scope of works..  (because without these- some built in contractor just like to short cut things specially on the material selection and the construction method)
7) Etc
8) and how many times they allow on the changes of design -how many proposal they allow for client to amend.

best of luck on your renovation....

cheers mate
izwan
www.archidstudio.com

Don’t forget full house Reno like that ID works will take cost of 30-40% of total Renovation works
Example your Reno  is 300k …(without ID fee) 30-40 percent is ID works ..120k (40%) balance is your wet works 180k …  ( don’t know is sufficient or not for your wet works - concreting , brick and plastering works etc)
Cheers mate
Izwan
Www.archidstudio.com