Your friend is correct in saying that your stones should be consistent, but he is incorrect in saying that you can only go for either territory or influence. A balance can be reached and that style of balancing territory and influence is what I play for. The key is to make sure that you are still being consistent with the stones you've already played.
The Low Chinese is my favorite opening. It aims for both territory and influence using a mix of low and high stones. This opening is played by many professionals. Take your pick of a pro, look through their games, and you will either find them playing this opening or having it played against them on a regular basis.
$$Bcm1 The Low Chinese Opening
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- Click Here To Show Diagram Code
[go]$$Bcm1 The Low Chinese Opening
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I would generally trust someone who is 1 kyu to be able to instruct a DDK player, so I'm sure other factors on the board were taken into account when he said your move wasn't right. You should know that there are many board positions where those moves would be playable. The other stones on the board really matter when it comes to the decision to play K4 or K3. An R10 stone matters, but the corner situation on both sides matters as well. For example:
$$Bcm1 Possible Sanrensei Opening
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- Click Here To Show Diagram Code
[go]$$Bcm1 Possible Sanrensei Opening
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I personally feel that

is better here than at 'a' because it isn't undercut by

. Obviously 'a' is also fine, but I don't think you can argue that

is wrong because

is high.
I couldn't find this exact position in a quick look on Go4Go, but here's an example of a pro game where black played K3 in spite of all his high stones on the right.
$$B Takemiya Masaki 9p (B) vs. Hane Yasumasa 9p (W)
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$$ +---------------------------------------+
- Click Here To Show Diagram Code
[go]$$B Takemiya Masaki 9p (B) vs. Hane Yasumasa 9p (W)
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$$ +---------------------------------------+[/go]
And I'm sure Takemiya considered his R10 stone when he played this, but he also considered the white corner stone that is now undercut on both sides by his move and his own corner stone that this becomes a nice 5-space extension from. White proceeded to invade black's 3-3 point immediately, then white made a living group in the center above the K3 stone, but black ended up winning by resignation after white failed to invade black's area on the left.
All-in-all, don't worry too much about developing a style. That will come naturally. Just play games to win and feel free to experiment. Try a game playing all for influence. Try one playing all for territory. Try one were you go for a mix. The key at all kyu stages (and at dan stages as well) is to keep learning and getting stronger.