Find the ciphering method 4

Question

Link to the entire series.

The message:

A U J A H M N Q G B U B A W Q W Q M Q R 
N W N G Q G P U M S T Z A N G U O W R M 
R L H M O W O P W N X Z R U O T X U X I 
N K N W M N B A B H E O W P M M O H T G 
P Y A G G Y H S Y K N G Q U Y A Z J P G 
Y W M N Y R E Y K K U W Z W B E Y S J B 
R R C Y R Z H O Y M P C O X T M X V U P 
Y W M O Z K E S P B Q W Q E S Y T N M B 
R W Z N P R U B J E M G O Q F A B U A O 
W R A H B K T O Z B S Q K M U H A J E N 
K Q R N R Z R A O J O T F J K Z Q N S A 
O W K Q P A M M F A P A F B W R G F J F 
M D M R Z M G L U X B E X M V Z T W I U 
Y S A M G Q N Z K H U U U Y F R Y Z P W 
E R D B S R O F A A F X B B O X I U X J 
E U G J T W T H N Y E Z S Z Y Y Z Q E Z 
M L Q X R N T I W S E R B G V R M G N Q 
N N W F B U M Q T T H N O R N W H U J J 
U A S G E E M E K O Z S P T M T O A B S 
N A Q B N K Y P B T G H W U M W O N M N

The answer:

FLUTE

Hint 1:

Look at row composition

Hint 2:

Some rows have letters that others do not have.

Hint 3:

X marks the spot row. And not only X.

Answer 1

The encryption method was to:

1. Start with the input
2. Apply a ROT3 Encryption
3. Convert the characters to A1Z26
4. Square the A1Z26
5. Convert the A1Z26 to roman numerals
6. Embed the roman numerals in the crossword

Table of steps:

ROMAN	ARABIC	SQRT	A1Z26	ROT3
LXXXI	81	9	I	F
CCXXV	225	15	O	L
DLXXVI	576	24	X	U
DXXIX	529	23	W	T
LXIV	64	8	H	E

Image with highlighted characters: