Color Row Based On Fixed Cell & Relative Cells

My sales spreadsheets have a column which is turned to 100% when the order comes in (i.e. when the salesman gets it in his commission). I have applied conditional formatting to turn the whole row green when this happens (for ease of seeing which orders are in)

We also have a cell for the Purchase Order "number" (as these come from the customer, these can be a straight number sequence - "12345" or a mix of letters and numbers - "ABC12345"). My boss would like this cell to be red if the "order in" column is at 100%, but there is no PO number.

However, when I put in the formatting:
(1) =$K$15=1 (to turn the row green)
(2) Cell Value is equal to 0 (to turn the cell red)

it will apply (1) no problem, but will only apply (2) if (1) is false. (i.e. if (1) is true, the whole row goes green, with no red in the PO box.)

If I switch them round (i.e. have (2) first), then I get the formatting that I want (i.e. green row with a red box), but if (1) is false, I still get a red PO box.

What I need is a way of only applying (2) if (1) is true. (or any other way of only making the PO box red if the order is 100% but there is no PO number)

• Color Code Cells Based On Value In Row 1 And Value In Cell
• Color Cells Based On Color Of Preceeding Cell
• Returning A Row Of Cells Based On A Color
• Color Row Range Based On Cell On Same Row
• Change Cell Color Relative To Another
• Insert Row At Active Cell With Formula From Fixed Row
• Delete Entire Row Based On A Cell Color
• Format Cells Color Based On 1 Cell
• Format Color For Range Of Cells Based On Cell Value
• Change Color Of All Cells On Sheet Based Off Of One Cell Value
• Format Cell Color Based On Others Cells Not Being Blank
• Chart With VBA Based On A Row With Values That Will Color The Offset Cell Interior Red And Also Give It A Value Of 1
• Color Column Charts Based On Font Color Data Cells
• Macro To Color Cells Based On Their Font Color
• Countif Based On Relative Cell
• Add Relative Row Formula To Cell
• Return Relative Cell Based On Condition
• Color Cell Fonts Based On Text Color Of TextBox Controls On UserForm
• Setting Color Of Range Based On Adjacent Cell Color
• Change Font Color Based On Adjacent Cell Color
• Change Text Color Based On Cell Color
• Paste Formula Across Rows But Change Relative Cell Reference To Column From Row
• Formatting Row Of Cells Based On A Cell Content
• Colour Range Of Cells In A Row Based On Value Of One Cell
• Selecting A Range Of Cells Relative To The Current Cell
• Color Cells Based On Adjacent Cells Being Empty & Add Text
• Color Rows Based On Row Citeria
• Copy Row Based On Color Index
• Conditional Formatting - Color Groups Based On Row Value
• Hide Row Based On Color Column I Being Present
• Looking Up Column Header Value Based On Color And Position In Row
• Fill Cells Color In Worbook Based On Other Cells
• Color Cells Based On Multiple Conditions Of Different Cells
• To Change The Color Of An Entire Row Based On The Value Of A Single Column
• Color Cells Based On Others
• Color Cells Based On Value Above/Below
• Color Cells Based On Difference Between Two Cells
• Copy Cells Based On Color
• Color Cells Where Column X Same Row Has Text
• Count Cells Based On Font Color
• Color Rows Based On Cells Being Greater Than/Less Than X
• Macro To Color Cells Based On Criteria
• Copy Cells Based On Fill Color
• Deleting Cells Based On Font Color
• Color Fill Cells Based On Value Being Between 2 Values
• Sum Cells Based On Color Index
• Color Cells Within Matrix Based On Conditions Outside
• Delete Cells Based On Fill Color
• Count Cells Based On Background Color
• Color Cells Based On Entry. More Than 3 Conditions