Help getting that fruity starter smell

The smell and flavor of your starter indicate how much fermentation has taken place.  The rate of fermentation is dependent on temperature, time, and quantity of available food.  If the temp is fluctuating while you are holding everything else the same, that could be the reason for the different results.  If there is variation in your whole wheat flour, that could also affect the speed of fermentation.

I do wonder about adding ice water to a starter- cool room temp water might be better.  Wild yeasts are so delicate, they are easily killed off by warm (above 90) or cold temps that commercial yeast might be fine with.

AP or Bread flour- either will do the job of feeding your culture, but the higher protein content of bread flour will hold up better when faced with the high enzymatic activity of a starter (especially a liquid starter like yours).  I use KAF AP to feed my starter because it has higher protein than other AP flours, yet comes in an encomical 10 lb bag and so is much more cost-efficient than other bread flours.

about a year and a half ago. I've always fed mine with 74-78F water and room temp. 50/50 flour and have never refrigerated it. I feed twice a day at 12 hr. intervals and let my starters smell and taste dictate how much seed I use. If it's very sour after 12 hrs. I will up the water temp to around 78-80 and lower the amount of seed (as low as 5%). If it's bland-ish after 12 hrs. I will lower the water temp to around 74-76 and up the seed amount to 20-30%. My room temp stays around 75F year 'round. My starter usually, but not always, smells sweet and fruity after 2 hrs. if fed around a 20% seed and 75F water and much longer if I use a small % of seed. I've never used cold water or flour as that would slow my fermentation way down and I use it everyday. This is just how I do it and there are many ways to maintain a viable starter. I also just fed my mother starter like this daily and build my leaven off it for work with 2-5% seed every evening keeping my mother and leaven separate. Hope this helps. I generally get the fruity smell about 2 hrs before my mother starter peaks.

If your looking for the sweet fruity smell then try dropping the WW and just use white flour.  I keep three starters white,  ww and rye.  The white is always sweet almost a vanilla smell while the ww and rye tend to be more sour smelling.

I keep three because each are so different.   For instance I like the W/W bread I make using a starter that was born and raised on W/W flour.  The smell and taste of the finished bread is so much different from a W/W inoculated with a white starter.  The rye is the same.  Some people may disagree but that is just my opinion.  So I do what makes me happy and bake to my taste.

If your  starter is rising too quickly then try reducing the seed amount rather than using cold water.

There are two main reasons to keep an ongoing culture separate from your bread builds.  The first is to eliminate the risk of using all your culture in the bread and forgetting to leave some out to perpetuate the culture.  I'll confess I did this once and had to restart my culture by rinsing out the starter jar and using that tiny bit of culture to build on.  Took a few days but it succeeded.  

The second is if you have different goals for the culture vs. the bread build.  For instance, if you want to keep your ongoing culture at 60% hydration because you like the balance of enzymes and acids, but want to build a bread culture at 100% hydration to get different characteristics.   Or if, like in the Tartine book, you want to use the bread build when the culture is young (has fermented less) but need to feed the ongoing culture when it is mature (has fermented more).   You might find it simpler to just keep them separate.

a WW Desem, Rye sour and one Multi-grain now it is Kamut since that was the last bread I made with it.  I start out with 70 g of each at 65% hydration an always keep them in the fridge.  I use about 10-20 g per bake.  When they get own to 10 g I refresh them back to 70 g.  Never fee them otherwise and they will last for a few weeks no worries in the fridge.  No feeding, no waste no hassles of any kind.  You have to build levain for bread anyway and they double in 6 hours for bread in the summer.

I second the idea about switching to an all-white flour starter for that fruityness you desire.  In my personal experience my starters with more whole grains give more of an earthy-wheaty flavor, tending to a more sour smell later in their development.  When I feed my all-white starter a few times, at short intervals (8 hours or less) is when I get that more over-ripe fruit smell (sweet too if you feed it on an even more intense schedule).  Of course, the local micro-flora and fauna for you may be much different than mine.