In Corona, there's not really such thing as upping the settings... There's just changing balance of sampling, not increasing it... what you did with your setting was increasing amount of GI sampling and direct light sampling at the expense of AA sampling... You need more GI sampling and direct light sampling in scenes with difficult direct light and indirect light paths... such as very small windows, lot's of bouncing before light gets to the rendered surface, and so on.
Since your interiors are not that difficult, defaults would do just fine. If you increase GI/AA balance and LSM, you may get cleaner surface, but worse antialiasing. There is not much fine geometric detail or textures in your scene, it will probably not do any harm, but you should keep in mind that antialiasing also takes care of DoF... so for shots with significant DoF effect, it is sometimes wise to actually decrease GI/AA balance, to get more samples for AA and therefore DoF. It is also not hard to figure out if you should. If focused areas clean up faster than areas out of focus, then decrease GI/AA balance. If focused areas clean up slower than areas out of focus, then increase it ;)
