Option Strike Prices
You will need to create the following Indicators 

A1 

A1:=If(C<=2.5,LastValue(2.5),If(C<=5,LastValue(5), 
If(C<=7.5,LastValue(7.5),If(C<=10,LastValue(10), 
If(C<=12.5,LastValue(12.5),If(C<=15,LastValue(15), 
If(C<=17.5,LastValue(17.5),If(C<=20,LastValue(20), 
If(C<=22.5,LastValue(22.5),If(C<=25,LastValue(25), 
C)))))))))); 
A1; 

A2 

A2:=If(C<=30,LastValue(30),If(C<=35,LastValue(35), 
If(C<=40,LastValue(40),If(C<=45,LastValue(45), 
If(C<=50,LastValue(50),If(C<=55,LastValue(55), 
If(C<=60,LastValue(60),If(C<=65,LastValue(65), 
If(C<=75,LastValue(75),If(C<=80,LastValue(80), 
If(C<=85,LastValue(85),If(C<=90,LastValue(90), 
If(C<=95,LastValue(95),If(C<=100,LastValue(100), 
C)))))))))))))); 
A2; 

A3 

A3:=If(C<=110,LastValue(110),If(C<=120,LastValue(120), 
If(C<=130,LastValue(130),If(C<=140,LastValue(140), 
If(C<=150,LastValue(150),If(C<=160,LastValue(160), 
If(C<=170,LastValue(170),If(C<=180,LastValue(180), 
If(C<=190,LastValue(190),If(C<=200,LastValue(200), 
If(C<=210,LastValue(210),If(C<=220,LastValue(220), 
If(C<=230,LastValue(230),If(C<=240,LastValue(240),C)))))))))))))); 
A3; 

A4 

A4:= If(C<=250,LastValue(250),If(C<=260,LastValue(260), 
If(C<=270,LastValue(270),If(C<=280,LastValue(280), 
If(C<=290,LastValue(290),If(C<=300,LastValue(300), 
If(C<=310,LastValue(310),If(C<=320,LastValue(320), 
If(C<=330,LastValue(330),If(C<=340,LastValue(340), 
If(C<=350,LastValue(350),If(C<=360,LastValue(360), 
If(C<=370,LastValue(370),If(C<=380,LastValue(380),C)))))))))))))); 
A4; 

A5 

A5:=If(C<=390,LastValue(390),If(C<=400,LastValue(400), 
If(C<=410,LastValue(410),If(C<=420,LastValue(420), 
If(C<=430,LastValue(430),If(C<=440,LastValue(440), 
If(C<=450,LastValue(450),If(C<=460,LastValue(460), 
If(C<=470,LastValue(470),If(C<=480,LastValue(480), 
If(C<=490,LastValue(490),If(C<=500,LastValue(500), 
If(C<=510,LastValue(510),If(C<=520,LastValue(520), 
C)))))))))))))); 
A5; 

A6 

A6:=If(C<=510,LastValue(510),If(C<=520,LastValue(520), 
If(C<=530,LastValue(530),If(C<=540,LastValue(540), 
If(C<=550,LastValue(550),If(C<=560,LastValue(560), 
If(C<=570,LastValue(570),If(C<=580,LastValue(580), 
If(C<=590,LastValue(590),If(C<=600,LastValue(600), 
If(C<=610,LastValue(610),If(C<=620,LastValue(620), 
If(C<=630,LastValue(630),If(C<=640,LastValue(640), 
C)))))))))))))); 
A6; 

Option Strike 

A7:=If(C<=25,2.5,If(C>25 AND C<100,5,10)); 
A8:=If(C<=25,Fml("A1"),If(C>25 AND C<=100,Fml("A2"),If(C<=240, 
Fml("A3"),If(C<=380,Fml("A4"),If(C<=520,Fml("A5"),Fml("A6")))))); 
UPStrike2:=LastValue(A8+(A7*2)); 
UPStrike1:=LastValue(A7+A8); 
UPStrike:=LastValue(A8); 
DNStrike:=LastValue(A8-A7); 
DNStrike1:=LastValue(A8-(A7*2)); 
DNStrike2:=LastValue(A8-(A7*3)); 
UPStrike2; 
UPStrike1; 
UPStrike; 
DNStrike; 
DNStrike1; 
DNStrike2;