Глюки VB - точность вычислений (Single, Double)

Dim a As Double
 a = 3.6 / 2 - 7.2 / 4

DefDbl D
DefInt I, K
DefLng L
DefStr S
DefSng N, Q
Dim sf, shomedir As String
Dim kK, kn, kr, kvse, kmnu, kr1, kvnp, krkf As Integer
Dim iraschet As Integer 
Dim iris As Integer 
Dim kprint As Integer
Dim lraz As Long 
Dim lxmin, lxmax, lymin, lymax As Long 
Dim lbr As Long 
Dim lrazk 
Dim f(1 To 1000, 1 To 22) As Single
Dim s(1 To 1000) As String
Dim qd(1 To 1000, 1 To 7) As Single
Dim qgg(1 To 1000, 1 To 8) As Single
Dim kda(1 To 14) As Integer
Dim kch As Integer 
Dim kppr As Integer 
Dim kuso As Integer 
Dim kppr1 As Integer 
Dim ny, nmrs, nrb, nrbt As Single
Dim qpp, qm11, qm22, qt11, qt22 As Single 
Dim ikoa, ikob As Integer 
Dim qeb, qea, qmbs, qmas, qpn, qmb1, qma1, qmb2, qma2, qpmb, qpma, qpmx, qpmn As Single
Dim qdpmax, qdpmin, qdta, qdtb, qdma, qdmb, qd1, qd2, qd3, qd4, qd5, qd6, qd7, qatrans, qbtrans, qxx, qyy, qd66, qd77 As Single
Dim ltip(1 To 1000) As Long
Dim sot As String 
Dim nrra, nrra1, nl, ngmin11, nm, nq, nh0, na, nb, nsrh, nam, ner, nar As Single 
Dim iog As Integer 
Dim ipic(1 To 9) As Integer 
Dim nsh1 As Single 
Dim qm1, qt1, qm2, qt2, qp As Single 
Dim nsva1, nsva2, nsva3, nsva11, nsva12, nsva13, nsvb1, nsvb2, nsvb3, nsvb11, nsvb12, nsvb13, nh1, nh2, nh3 As Single
Dim nl1, nl11, nl2, nl12, nl3, nl13, nl4, nl14, nl5, nl15, nl6, nl16 As Single
Dim iprod, iprod1 As Integer 
Dim nkiom, nkioq, nkipm, nkipq, nkipp, nkir As Single

If (na / 2 - nl4 - nl5 - f(iprod, 20) / 2000 + f(iprod, 22) / 1000) <=0 And nh3 <> 0 And (nb / 2 - nl1 - nl2 - f(iprod, 19) / 2000 + f(iprod, 21) / 1000) <=0 Then
MsgBox "Сообщение !", vbCritical, "Расчет фундамента"
iprod = iprod + 1
End If

If (na / 2 - nl4 - nl5 - f(iprod, 20) / 2000 + f(iprod, 22) / 1000) < 0.001 And nh3 <> 0 And (nb / 2 - nl1 - nl2 - f(iprod, 19) / 2000 + f(iprod, 21) / 1000) < 0.001 Then
MsgBox "Сообщение !", vbCritical, "Расчет фундамента"
iprod = iprod + 1
End If

Dim f(1 To 1000, 1 To 22) As Single
Dim na As Single
Dim nl4, nl5 As Single
Dim iprod As Integer
 
Private Sub Command1_Click() ' щелкаем по кнопочке
na = 3.3: nl4 = 0.75: nl5 = 0.6: iprod = 1: f(iprod, 20) = 600: f(iprod, 22) = 0
If (na / 2 - nl4 - nl5 - f(iprod, 20) / 2000 + f(iprod, 22) / 1000) = 0 Then
MsgBox "Сообщение !", vbCritical, "Расчет фундамента"
iprod = iprod + 1
End If
 
End Sub

If (na / 2 - nl4 - nl5) = (f(iprod, 20) / 2000) Then na = na

Debug.Print CDec(na / 2 - nl4 - nl5) - CDec(f(iprod, 20) / 2000)
If (CDec(na / 2 - nl4 - nl5) - CDec(f(iprod, 20) / 2000) + f(iprod, 22) / 1000) = 0 Then

Private Sub Command1_Click() 
If 1.65 - 0.75 - 0.6 - 0.3 = 0 Then
MsgBox "Сообщение !", vbCritical, "ГЛЮК"
End If
 
End Sub

Private Sub Command1_Click()
If Abs(1.65 - 0.75 - 0.6 - 0.3) < 0.000001 Then
MsgBox "Сообщение !", vbCritical, "ГЛЮК"
End If
 
End Sub
 
Private Sub Command2_Click()
If Round((1.65 - 0.75 - 0.6 - 0.3), 5) = 0 Then
MsgBox "Сообщение !", vbCritical, "ГЛЮК"
End If
End Sub
 
Private Sub Command3_Click()
 
If FormatNumber(1.65 - 0.75 - 0.6 - 0.3, 4) = 0 Then
MsgBox "Сообщение !", vbCritical, "ГЛЮК"
End If
 
End Sub