Javascript for adobe acrobat, what am I doing wrong

Hi I am new to doing fillable forms and am having troube making if statements that require 3 conditions.

I am trying to get numbers within a certain range to correct. I will post what I have done. 

var PLIGHT1 = Number(this.getField("PLIGHT1").valueAsString);
var LMN = Number(this.getField("LMN").valueAsString);

if (LMN=="7" && (PLIGHT1 => 1 && PLIGHT1 < 767)) {
event.value = (0.99*PLIGHT1);
}
else if (LMN=="7" && (PLIGHT1 => 767 && PLIGHT1 < 1022)) {
event.value = (0.98*PLIGHT1);
}
else if (LMN=="7" && (PLIGHT1 => 1022 && PLIGHT1 < 1552)) {
event.value = (0.98*PLIGHT1);
}
else if (LMN=="7" && (PLIGHT1 => 1552 && PLIGHT1 < 2060)) {
event.value = (0.97*PLIGHT1);
}
else if (LMN=="7" && (PLIGHT1 => 2060 && PLIGHT1 < 2562)) {
event.value = (0.97*PLIGHT1);
}
else if (LMN=="7" && (PLIGHT1 => 2562)) {
event.value = (0.98*PLIGHT1);
}
if (LMN=="6" && (PLIGHT1 > 1 && PLIGHT1 < 799)) {
event.value = (0.96*PLIGHT1);
}
else if (LMN=="6" && (PLIGHT1 => 800 && PLIGHT1 < 1055)) {
event.value = (0.94*PLIGHT1);
}
else if (LMN=="6" && (PLIGHT1 => 1055 && PLIGHT1 < 1613)) {
event.value = (0.95*PLIGHT1);
}
else if (LMN=="6" && (PLIGHT1 => 1613 && PLIGHT1 < 2142)) {
event.value = (0.93*PLIGHT1);
}
else if (LMN=="6" && (PLIGHT1 => 2142 && PLIGHT1 < 2649)) {
event.value = (0.93*PLIGHT1);
}
else if (LMN=="6" && (PLIGHT1 => 2649)) {
event.value = (0.94*PLIGHT1);
}
else event.value = "";

when I try to use it it will only correct with 6 selected if I use 7 it is blank, I would really appreciate it if anyone can point out what I am doing wrong. Thank you.