Deco is SUCH a small part of planning at that level that all that is really needed is a knowledge of no-stop times at given depths, ie tables.
Run EAN32 as standard and you will not hit deco on a single cylinder dive, unless you are WAY beyond your depth limit.
Dive planning is now about min gas (1200L or 100bar in a single 12L from 30m, or 80 bar from 18m and above). Subtract 80 bar from your start pressure, choose your gas planning model (all in, halves or thirds) and then work backwards to available time based on bar/min SAC. SAC of 2 bar/min at surface is 5 bar/min at 15m. 230 bar fill? 150 bar useable gas. That's 30 mins all in, or turn at 15min/155bar for halves or 10 min/180bar for thirds. Super frickin simple.
30 mins at 18m is SO far short of deco it ain't even worth worrying about.
Concentrate on the REAL essentials of diving - buoyancy and trim. Everything else is easy after that...